Add Node 7 to CI (#5165)
Add Node 7 to CI (#5165)

This reapplies this commit, as it was lost before

samwgoldman/babel,vadzim/babel,ccschneidr/babel,shuhei/babel,chicoxyzzy/babel,jridgewell/babel,hulkish/babel,hzoo/babel,maurobringolf/babel,hulkish/babel,kedromelon/babel,guybedford/babel,STRML/babel,chicoxyzzy/babel,chicoxyzzy/babel,PolymerLabs/babel,kaicataldo/babel,Skillupco/babel,Skillupco/babel,babel/babel,samwgoldman/babel,kaicataldo/babel,hzoo/babel,STRML/babel,kellyselden/babel,kaicataldo/babel,jridgewell/babel,existentialism/babel,hzoo/babel,existentialism/babel,guybedford/babel,maurobringolf/babel,kellyselden/babel,claudiopro/babel,shuhei/babel,kellyselden/babel,babel/babel,Skillupco/babel,existentialism/babel,kellyselden/babel,shuhei/babel,PolymerLabs/babel,samwgoldman/babel,babel/babel,guybedford/babel,babel/babel,hulkish/babel,jridgewell/babel,Skillupco/babel,hzoo/babel,claudiopro/babel,PolymerLabs/babel,maurobringolf/babel,chicoxyzzy/babel,kaicataldo/babel,claudiopro/babel,ccschneidr/babel,jridgewell/babel,hulkish/babel,vadzim/babel,kedromelon/babel,kedromelon/babel