[2/2] OmniGears: Clock tweaks

PS5:
- added slims clock and date customizations for status bar
PS6:
- Remove color preference
- Refactored code
PS7/8:
- Fixed build
PS9:
- Fixed FC
PS10:
- Display date style & format if it is disabled

Base: https://gerrit.omnirom.org/#/c/4938/

Change-Id: I6d9a1db1717cbe08ed275c8cca21ec2ace7e96c4
Merge "[2/2] OmniGears: Clock tweaks" into android-4.4