Fwk: Adding a micro theme

Adding a micro theme affects 3 different GIT repositories:

1. Repository 'device/google/clockwork' - https://ar/398971
This has the overlay for the DeviceDefault for ClockWork

2. Repository 'platform/vendor/google_clockwork' - https://ar/399378
This has the changes to Clockwork Home to use the new micro Theme.

3. Repository 'frameworks/base' - https://ar/398959
This adds the *_micro.xml style/theme files.

Change-Id: Ib1e87953b052a9ec2ff0ea11dd0dfe55317442b4