Add ruby 2.1.0 to CI and drop 1.9.2
Add ruby 2.1.0 to CI and drop 1.9.2

jwhitcraft/sinatra-assetpack,flywithmemsl/sinatra-assetpack,flywithmemsl/sinatra-assetpack,flywithmemsl/sinatra-assetpack,rstacruz/sinatra-assetpack,rstacruz/sinatra-assetpack,rstacruz/sinatra-assetpack,jwhitcraft/sinatra-assetpack,jwhitcraft/sinatra-assetpack