Update travis.yml: ruby 1.9.3, 2.1.1, rbx-2
Update travis.yml: ruby 1.9.3, 2.1.1, rbx-2

amitree/activerecord-postgis-adapter,ericcj/activerecord-postgis-adapter,IBazylchuk/activerecord-postgis-adapter,dzjuck/activerecord-postgis-adapter