Began removing files that don't need to be in the repo.

- Removed the sample project.
- Removed sample APK.
- Removed IDE bin and gen folders.
- Removed IntelliJ IML files.
- Etc…
Addressed show/hide animation bugs.

The existing code base contained a bug where if the user rapidly
scrolled up and down on a ListView that the FAB was listening to, the
FAB would forget it’s original Y position and slowly scroll off screen
never to be seen again. This change fixes that by storing the FAB’s
resting Y position when it is first defined in onLayout and uses it
instead of the view’s current Y position when animating.