Grunt build now supports package CSS

Up until now we were just using LESS to compile our styles, however in
many cases this is either unecessary (because the library includes a
CSS file already) or impossible (because a third-party library ONLY
includes CSS). In order to support a library's plain-css includes,
I've used font-awesome as a demo library to show how compiling plain
CSS would work. Bootstrap remains a LESS include, since we're using
variables to customize it.

- Added CSS compile block to index.html including font-awesome.css
- Removed font-awesome from LESS compile.

Change-Id: I52af102e139628bb8ff71a7e2f4ae413708ceb6e
Merge "Grunt build now supports package CSS"