CraveOS constants

Change-Id: I2f947768ab33668ba900f458ae354507d6cce788
Custom Crave navigation bar

Change-Id: Ic1a3422ad7fa65889d9f7a343f9246c095e3231c
Custom Crave navigation bar #2

Change-Id: I76d42671cc0c9bdbb4a47091e5a8f5bba59ef1c9