Summary:
- The recent addition of `IGListCollectionViewLayoutInternal.h` in a80245a696 broke the example project. This PR fixes this.
- Name sorted the internal files
- [x] All tests pass. Demo project builds and runs.
- [x] Why didnt Travis catch this? 🤔
- [X] I added an entry to the `CHANGELOG.md` for any breaking changes, enhancements, or bug fixes.
- [X] I have reviewed the [contributing guide](https://github.com/Instagram/IGListKit/blob/master/.github/CONTRIBUTING.md)
Closes https://github.com/Instagram/IGListKit/pull/569
Differential Revision: D4740682
Pulled By: rnystrom
fbshipit-source-id: 2c57d03f9751d14edf35741eaa97d0ae8a2f167a
353d90f397