Clean up samples (gradle files and Compat stuff in wearable code).

- Remove -v13 and -v4 dependencies on wearable side
- Verify phone is set to compile on API 19 and wearable on 20
- Replace NotificationCompat in wearable side since it uses API 20
- Move ElizaChat code to Application directory

Bug: 15809453
Change-Id: Ib75e7894505f82e5b4d8591b4dfa91a3de8e0329
74 files changed