Simple whitelabeling

The LESS compiler resolves @import references on a 'first hit' basis,
allowing us to provide simple custom-theme support by providing a
directory with a higher resolution priority.

- Renamed the 'styles' directory to 'theme'
- Updated grunt-contrib-less version
- Added README for the super curious
- Moved files around to place files into their respective directories
- Added custom theme .less files to .gitignore
- Update build.

Change-Id: Ic55a6b463a993f58fc7f71ad51fe65b04601ed78
Merge "Simple whitelabeling"