Configure Travis CI to use node 4
Configure Travis CI to use node 4

jhen0409/react-devtools,mcanthony/react-devtools,aadsm/react-devtools,aarondancer/react-devtools,aolesky/react-devtools,aolesky/react-devtools,jhen0409/react-devtools,MichelleTodd/react-devtools,woowe/react-dev-tools,allofthenorthwood/react-devtools,aarondancer/react-devtools,aolesky/react-devtools,aarondancer/react-devtools,hedgerwang/react-devtools,Jonekee/react-devtools,mcanthony/react-devtools,allofthenorthwood/react-devtools,aadsm/react-devtools,hedgerwang/react-devtools,aadsm/react-devtools,woowe/react-dev-tools,Jonekee/react-devtools,woowe/react-dev-tools,keyanzhang/react-devtools,MichelleTodd/react-devtools,hedgerwang/react-devtools,jhen0409/react-devtools,keyanzhang/react-devtools