Adding unlock-like slider control for alarm dismiss/snooze.

This is a re-addition of something that was previously added and then removed:
I65be41b889446ae7232488bfc2809bd2add93f6f

- Ported GlowPadView and helper classes over to clock app.  Framework version
  relies on a couple hidden api's so there are minor changes to the code.
- Added necessary drawables to support slider.
- Added special paddings for 7" and 10" tablet.

Bug: 7353387
Change-Id: I6101bebdb4be6f0208d171fbfadc4317f9fac675