Move Compass linters into separate README

The Compass linters (well, currently just linter) deserve a section of
there own so as to not overcrowd the main README. Instead, we link from
the main README to the individual one for Compass.

Change-Id: I6264e5f8b5e422fecc0c113a973691c870aafc2e
Reviewed-on: https://gerrit.causes.com/33672
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>