zeppelin/docs/usage
Nelson Costa e1f20ddda2 [ZEPPELIN-2699] Helium REST API bug-fixes. Also updated documentation
### What is this PR for?
Fixing bug on enabling Helium plugins (artifact is empty, not null) when sending curl command.
After noticing out-of-date documentation, I updated it
Also noticed issues on missing try/catch expressions and missing info messages on enable/disable packages.

### What type of PR is it?
[Bug Fix | Documentation | Refactoring]

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-2699

### How should this be tested?
Run "curl -X POST http://localhost:8080/api/helium/enable/{packageName}"
Check that the package gets enabled

### Questions:
* Does the licenses files need update? N
* Is there breaking changes for older versions? N
* Does this needs documentation? Y (Done)

Author: Nelson Costa <nelson.costa85@gmail.com>

Closes #2446 from necosta/zeppelin2699 and squashes the following commits:

473f9b43 [Nelson Costa] [ZEPPELIN-2699] Fixed initialization issue
45b77513 [Nelson Costa] [ZEPPELIN-2699] More corrections
c8230218 [Nelson Costa] [ZEPPELIN-2699] Bug-fix on gathering package info
2b1ff8ae [Nelson Costa] [ZEPPELIN-2699] Changes after code review
a71b9fb9 [Nelson Costa] [ZEPPELIN-2699] Changes after code-review
5d179218 [Nelson Costa] [ZEPPELIN-2699] Helium REST API bug-fixes. Also updated documentation
2017-07-22 00:24:20 +09:00
..
display_system [ZEPPELIN-2707][DOCS][HOTFIX] fix: broken image URLs in 0.8.0-SNAPSHOT doc 2017-06-30 10:33:01 +09:00
dynamic_form [ZEPPELIN-2707][DOCS][HOTFIX] fix: broken image URLs in 0.8.0-SNAPSHOT doc 2017-06-30 10:33:01 +09:00
interpreter [ZEPPELIN-2582][DOCS] docs for interpreter binding modes 2017-07-07 16:23:49 +09:00
other_features [ZEPPELIN-2707][DOCS][HOTFIX] fix: broken image URLs in 0.8.0-SNAPSHOT doc 2017-06-30 10:33:01 +09:00
rest_api [ZEPPELIN-2699] Helium REST API bug-fixes. Also updated documentation 2017-07-22 00:24:20 +09:00