DO NOT MERGE Slight UX tweaks to Dialer

* Add drawable and apply to dialpad fragment for shadow effect
* Tweak name/number padding in tiles
* Tweak default letter avatar placing in tiles
* Add shadow for dialpad
* Swap out 9patch drawable for recents
* Add 9patch to contact tile

Bug: 13421236
Bug: 13418523
Bug: 13421916
Bug: 13421236
Bug: 13419201
Bug: 13418712

Change-Id: I6ff8fe41d7e2d02db105bb542f425be13ae5fef7