Improved travis config
Improved travis config

rossriley/flysystem,twistor/flysystem,hannesvdvreken/flysystem,oswaldderiemaecker/flysystem,farmisen/flysystem,sohelrana820/flysystem,mhlavac/flysystem,barryvdh/flysystem,mhlavac/flysystem,CarsonF/flysystem,mapyo/flysystem,nao-pon/flysystem,dstockto/flysystem,twistor/flysystem,sachintaware/flysystem,concrete5/flysystem,dshafik/flysystem,Amrit01/flysystem