fix #106 immutablejs warnings about length
fix #106 immutablejs warnings about length

allofthenorthwood/react-devtools,MichelleTodd/react-devtools,zhjlty/react-devtools,arm22/react-devtools,hcxiong/react-devtools,hasErico/react-devtools,conorhastings/react-devtools,IveWong/react-devtools,woowe/react-dev-tools,MichelleTodd/react-devtools,aolesky/react-devtools,keyanzhang/react-devtools,IveWong/react-devtools,EasonYi/react-devtools,wangcan2014/react-devtools,hedgerwang/react-devtools,mojaray2k/react-devtools,aolesky/react-devtools,jhen0409/react-devtools,aolesky/react-devtools,syejing/react-devtools,reidwooten99/react-devtools,syejing/react-devtools,jaredly/react-devtools,jhen0409/react-devtools,hedgerwang/react-devtools,mcanthony/react-devtools,jayphelps/react-devtools,jayphelps/react-devtools,keyanzhang/react-devtools,hcxiong/react-devtools,mcanthony/react-devtools,Jonekee/react-devtools,aadsm/react-devtools,woowe/react-dev-tools,wangcan2014/react-devtools,allofthenorthwood/react-devtools,MarcoPai/react-devtools,arch-js/react-devtools,hasErico/react-devtools,aarondancer/react-devtools,jryans/react-devtools,MarcoPai/react-devtools,arm22/react-devtools,jryans/react-devtools,modulexcite/react-devtools,jaredly/react-devtools,zhjlty/react-devtools,aadsm/react-devtools,hedgerwang/react-devtools,mojaray2k/react-devtools,reidwooten99/react-devtools,EasonYi/react-devtools,modulexcite/react-devtools,arch-js/react-devtools,conorhastings/react-devtools,aarondancer/react-devtools,aarondancer/react-devtools,Jonekee/react-devtools,woowe/react-dev-tools,aadsm/react-devtools,jhen0409/react-devtools