Add Bower version badge to README

Change-Id: Ia6c7d42ae3bc4236f16c753a7b0c2b15db92c016
Reviewed-on: http://gerrit.causes.com/37567
Reviewed-by: Joe Lencioni <joe.lencioni@causes.com>
Tested-by: Joe Lencioni <joe.lencioni@causes.com>