Settings: Transparent navbar and more (2/2)

This commit introduces transparent navigation bar. Also colorizing method
changed.

- custom transparency
- custom color
- custom transparency mode (linked with statusbar transparency mode)
  0 = launcher, 1 = launcher and lockscreen, 2 = always
- Settings fits now with new functions

cheers

Change-Id: Icd1ef42ad461cb01b7a5964c4f5ccc7debb81b64