Heads Up custom colors, (1/2):

Based on SlimRoms:
https://github.com/SlimRoms/frameworks_base/commit/e1932cb5cdf0d75e226d4f82bc930d660aaae136

Included:
- Custom background color, (heads up and snooze button)
- Custom background pressed color, (heads up and snooze button)
- Custom icon color, (heads up and snooze button)
- Custom text color
- Option to enable/disable colorizing the notification icon