Removed io from travis build, as es6-promise fails on it
Removed io from travis build, as es6-promise fails on it

yusufsafak/cerebral,cerebral/cerebral,bradparks/cerebral__web_app_state_with_debugger,dsibiski/cerebral,bdjnk/cerebral,dsibiski/cerebral,fopsdev/cerebral,saulshanabrook/cerebral,idream3/cerebral,FWeinb/cerebral,Guria/cerebral,garth/cerebral,bradparks/cerebral__web_app_state_with_debugger,yusufsafak/cerebral,garth/cerebral,idream3/cerebral,bdjnk/cerebral,christianalfoni/cerebral,Guria/cerebral,saulshanabrook/cerebral,FWeinb/cerebral,christianalfoni/cerebral,cerebral/cerebral,fopsdev/cerebral