Summary:
- Fixes#105
- ~~Added a 'SpinnerSectionController' allowing us to trigger the activity spinner each time~~
- Changed the words array to be numbers instead (I found it personally difficult to realise if more cells were actually added as the text didn't seem to change, by using numbers you can quite clearly see it increment by 5 each time you load more)
- No changes/new tests as it is a fix to an example
- [x] All tests pass. Demo project builds and runs.
- [x] I added tests, an experiment, or detailed why my change isn't tested.
- [x] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/master/CONTRIBUTING.md)
Closes https://github.com/Instagram/IGListKit/pull/109
Differential Revision: D4066700
Pulled By: rnystrom
fbshipit-source-id: 7779a8ba39361cfa2e782db9460e693e90f1a478
