### What is this PR for?
As more and more document pages are added, it's really hard to find specific pages. So I added searching feature to Zeppelin documentation site([jekyll](https://jekyllrb.com/) based site) using [lunr.js](http://lunrjs.com/).
- **How does it work?**
I created [`search_data.json`](6e02423f54/docs/search_data.json) which is used for docs info template. `lunr.js` combines all of the text from all of the docs in `docs/` into `_site/search_data.json`. It looks like below.

All the info are comes from [Jekyll YAML front matter](https://jekyllrb.com/docs/frontmatter/) variables. (i.e. title, group, description.. that's why I rewrote all docs' title and description.)
[search.js](6e02423f54/docs/assets/themes/zeppelin/js/search.js) will do this job using this data!
### What type of PR is it?
Improvement & Feature
### Todos
* [x] - Keep consistency for all docs pages' `Title`
* [x] - Add some overview sentences to all docs pages' `Description` section (this will be used as the result preview)
* [x] - Add apache license header to all docs page (some pages are missing the license header currently)
* [x] - Add LICENSE for `lunr.min.js`
### What is the Jira issue?
[ZEPPELIN-1219](https://issues.apache.org/jira/browse/ZEPPELIN-1219)
### How should this be tested?
1. Apply this patch and build `ZEPPELIN_HOME/docs` dir -> please see [docs/README.md#build-documentation](https://github.com/apache/zeppelin/tree/master/docs#build-documentation)
2. Click `search` icon in navbar and go to `search.html` page
3. Type anything you want to search in the search bar (i.e. type `python`, `spark`, `dynamic` ... )
### Screenshots (if appropriate)


### Questions:
* Does the licenses files need update? Yes, for `lunr.min.js`
* Is there breaking changes for older versions? no
* Does this needs documentation? no
Author: AhyoungRyu <fbdkdud93@hanmail.net>
Closes#1266 from AhyoungRyu/ZEPPELIN-1219 and squashes the following commits:
7ec8854 [AhyoungRyu] Modify 'no result' sentence
91b71a7 [AhyoungRyu] Remove Apache license header since JSON doesn't allow comment
34afd5d [AhyoungRyu] Add Apache license header to search_data.json
6784282 [AhyoungRyu] Minor search page UI update
0389d28 [AhyoungRyu] Make index.md not to be searched
9f1ba42 [AhyoungRyu] Disable enterkey press & change icon
bd4956a [AhyoungRyu] Add docs.js & search.js to exclude list in pom.xml
624b051 [AhyoungRyu] Add Apache license header to search.js
1381152 [AhyoungRyu] Fix search result skipping issue
6e775f5 [AhyoungRyu] Make pleasecontribute.md not to be searched
ee11136 [AhyoungRyu] Fix some typos
fa01299 [AhyoungRyu] Refine 'description' in some docs as @bzz suggested
da0cff9 [AhyoungRyu] Exclude lunr.min.js
36ba7f1 [AhyoungRyu] Add lunr.min.js license info
f6a05a6 [AhyoungRyu] Apply css style for the search results
68eb997 [AhyoungRyu] Attach 'Apache Zeppelin ZEPPELIN_VERSION Documentation: ' to title
d908c37 [AhyoungRyu] Add searching page
a951fa6 [AhyoungRyu] Add search icon to navbar
0688a79 [AhyoungRyu] Keep consistency all docs' front matter for the right search result
040f532 [AhyoungRyu] Add template for storing docs info based on jekyll front matter
0705bd6 [AhyoungRyu] Add js files: lunr.min.js & search.js
### What is this PR for?
After #1087 merged, a new docs `shell.md` was added. But in the docs website, still Shell interpreter link points to `pleasecontribute.html`. So I changed this link, applied TOC and added more descriptions.
### What type of PR is it?
Documentation
### Todos
* [x] - Change `pleasecontribute.html` -> `shell.html`
* [x] - Apply TOC(table of contents)
* [x] - Add more description to `shell.md`
### Questions:
* Does the licenses files need update? no
* Is there breaking changes for older versions? no
* Does this needs documentation? no
Author: AhyoungRyu <fbdkdud93@hanmail.net>
Closes#1138 from AhyoungRyu/improve/shell-docs and squashes the following commits:
69d567d [AhyoungRyu] Address @felixcheung feedback
fca76a6 [AhyoungRyu] Apply TOC to rest-credential.md
c8e988b [AhyoungRyu] Change docs group manual -> interpreter
a0bf1d5 [AhyoungRyu] Add shell.html to _navigation.html
### What is this PR for?
I added auto TOC(Table of Contents) generator for Zeppelin documentation website. TOC can help people looking through whole contents at a glance and finding what they want quickly.
I just added `<div id="toc"></div>` to the each documentation header. [`toc`](https://github.com/apache/zeppelin/compare/master...AhyoungRyu:ZEPPELIN-1018?expand=1#diff-85af09fb498a5667ea455391533f945dR3) recognize `<h2>` & `<h3>` as a title in the docs and it automatically generate TOC. So I set a rule for this work. (I'll write this rule on `docs/CONTRIBUTING.md` or [docs/howtocontributewebsite](https://zeppelin.apache.org/docs/0.6.0-SNAPSHOT/development/howtocontributewebsite.html)).
```
# Level-1 Heading <- Use only for the main title of the page
## Level-2 Heading <- Start with this one
### Level-3 heading <- Only use this one for child of Level-2
toc only recognize Level-2 & Level-3
```
Please see the below attached screenshot image.
### What type of PR is it?
Improvement & Documentation
### Todos
* [x] - Add TOC generator
* [x] - Apply TOC(`<div id="toc"></div>`) to every documentation and reorganize each headers(apply the above rule)
* [x] - Fix some broken code block in several docs
* [x] - Apply TOC to `r.md` (Currently R docs has some duplicated info since [this one](d5e87fb8ba) and [this one](7d6cc7e991) )
* [x] - Apply TOC to `install.md` after #1010 merged
* [x] - Apply TOC to `interpreterinstallation.md` after #1042 merged
### What is the Jira issue?
[ZEPPELIN-1018](https://issues.apache.org/jira/browse/ZEPPELIN-1018)
### How should this be tested?
1. Apply this patch and build `docs/` with [this guide](https://github.com/apache/zeppelin/tree/master/docs#build-documentation)
2. Visit some docs page. Then you can see TOC in the header of page.
### Screenshots (if appropriate)
- Automatically generated TOC in Spark interpreter docs page
<img width="831" alt="screen shot 2016-06-16 at 9 37 18 pm" src="https://cloud.githubusercontent.com/assets/10060731/16140902/945b9c7a-340a-11e6-91f3-b6174738bed0.png">
### Questions:
* Does the licenses files need update?
No. Actually I used [jekyll-table-of-contents#copyright](https://github.com/ghiculescu/jekyll-table-of-contents#copyright). But I don't need to add a license for this :)
* Is there breaking changes for older versions? No
* Does this needs documentation? Maybe
Author: AhyoungRyu <fbdkdud93@hanmail.net>
Closes#1031 from AhyoungRyu/ZEPPELIN-1018 and squashes the following commits:
e66397b [AhyoungRyu] Apply TOC to interpreterinstallation.md
009579b [AhyoungRyu] Add more info to 'What is the next?' in install.md
04cf501 [AhyoungRyu] Revert 'where to start' section
b7cbe5f [AhyoungRyu] Fix typo
cf0911c [AhyoungRyu] Rename license file
388f35a [AhyoungRyu] Add jekyll-table-of-contents license info
6394c70 [AhyoungRyu] Fix image path in python.md
d00e4b1 [AhyoungRyu] Move interpreter/screenshot/ -> asset/../img/docs-img/
3ffb383 [AhyoungRyu] Remove duplicated info in r.md & apply toc
a03ca99 [AhyoungRyu] Exclude toc.js from pom.xml
3fae7df [AhyoungRyu] Apply auto generated toc to install.md
d114a9d [AhyoungRyu] Address @felixcheung feedback
6a788fe [AhyoungRyu] Resize TOC tab indent
6760c00 [AhyoungRyu] Apply auto TOC to all of docs under docs/storage/
fbde57f [AhyoungRyu] Apply auto TOC to all of docs under docs/quickstart/
db76eb6 [AhyoungRyu] Apply auto TOC to all of docs under docs/install/
f35db47 [AhyoungRyu] Apply auto TOC to all of docs under docs/displaysystem/
b05365f [AhyoungRyu] Apply auto TOC to all of docs under docs/rest-api/
163691c [AhyoungRyu] Apply auto TOC to all of docs under docs/manual/
bef398e [AhyoungRyu] Apply auto TOC to all of docs under docs/development/
9c5f76b [AhyoungRyu] Apply auto TOC to all of docs under docs/interpreter/
587d4ba [AhyoungRyu] Apply auto TOC to all of docs under docs/security/
1f10b97 [AhyoungRyu] Change toc configuration
78dca9e [AhyoungRyu] Add toc.js for auto generating TOC
### What is this PR for?
Supporting Sql completer into JDBC Interpreter which is merged by the function of Postgresql Interpreter. And this is the first step to merge Postgresql into generic JDBC Interpreter
### What type of PR is it?
[Improvement]
### Todos
* [x] - Adopted the function of auto completion
### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-614
### How should this be tested?
### Screenshots (if appropriate)
<img width="1054" alt="screen shot 2016-06-08 at 3 00 54 pm" src="https://cloud.githubusercontent.com/assets/3612566/15884224/e241f6b4-2d89-11e6-9746-8c8951ef6708.png">
<img width="474" alt="screen shot 2016-06-08 at 2 45 50 pm" src="https://cloud.githubusercontent.com/assets/3612566/15884229/e7993e24-2d89-11e6-9f5b-018e6eac7f6a.png">
### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No
Author: Jongyoul Lee <jongyoul@gmail.com>
Closes#974 from jongyoul/ZEPPELIN-614 and squashes the following commits:
998352c [Jongyoul Lee] Fixed old styles
99ce452 [Jongyoul Lee] Updated license document
d482395 [Jongyoul Lee] Fixed typo and coding style
e49f73c [Jongyoul Lee] Updated original documentation
6491cba [Jongyoul Lee] Added auto completion from PostgresqlInterpreter
Due to the documentation of interpreters written by various authors, styles of documentations are vary and has broken tags and inconsistent spaces. This fix cleans those little glitches to make documentation more readable and look cleaner to users.
1) Clean up unnecessary or wrong HTML tags ex: \<hr/\> after titles
2) Fix too wide spaces between paragraph and tables
3) Remove unnecessary spaces at end of paragraph and lines
Author: Jesang Yoon <yoonjs2@kanizsalab.com>
Closes#648 from yoonjs2/master and squashes the following commits:
eba0315 [Jesang Yoon] Merge remote-tracking branch 'upstream/master'
db8b4da [Jesang Yoon] Merge remote-tracking branch 'upstream/master'
781954b [Jesang Yoon] Interpreter documentation merge with commit #578af55811 [Jesang Yoon] Merge remote-tracking branch 'origin/master'
079480f [Jesang Yoon] Merge remote-tracking branch 'origin/master'
5f0a6e0 [Jesang Yoon] Merge remote-tracking branch 'origin/master'
4d1503a [Jesang Yoon] Merge remote-tracking branch 'origin/master'
5b091e4 [Jesang Yoon] Fix wrong HTML tags, indention and space between paragraph and tables. Remove unnecessary spaces.
5665dcf [Jesang Yoon] Fix wrong HTML tags, indention and space between paragraph and tables. Remove unnecessary spaces.
just notice this has typos too
Author: Felix Cheung <felixcheung_m@hotmail.com>
Closes#475 from felixcheung/postgresdoc and squashes the following commits:
08baa89 [Felix Cheung] fix broken link
3f728f3 [Felix Cheung] fix typos