UICollectionViewSupport for FirebaseUI

0.2.0 Release of Firebase UI includes:

1. FirebaseCollectionViewDataSource
2. Better support for Swift, including docs, nullability annotations, lightweight generics, and __kindof
3. Docs!

v0.1.2

Fixes to the Podspec that finally uploads to Cocoapods.

Initial Release of FirebaseUI

Initial release of FirebaseUI for iOS!