OmniGears: use OmniUtils

need https://gerrit.omnirom.org/5164

Change-Id: I06d321221174e706d45572159a5a827138303fe5
[2/2] OmniGears: Clock tweaks

PS5:
- added slims clock and date customizations for status bar
PS6:
- Remove color preference
- Refactored code
PS7:
- Fixed build

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

Change-Id: I6d9a1db1717cbe08ed275c8cca21ec2ace7e96c4

Conflicts:

	res/values/custom_arrays.xml
	res/values/custom_strings.xml