[skip ci] Add classPrivateProperties to README & fix classProperties proposal link (#554)
[skip ci] Add classPrivateProperties to README & fix classProperties proposal link (#554)


jridgewell/babel,babel/babel,Skillupco/babel,kellyselden/babel,samwgoldman/babel,chicoxyzzy/babel,shuhei/babel,shuhei/babel,babel/babel,babel/babel,jridgewell/babel,kaicataldo/babel,hzoo/babel,samwgoldman/babel,PolymerLabs/babel,hulkish/babel,chicoxyzzy/babel,hulkish/babel,Skillupco/babel,hulkish/babel,kellyselden/babel,kellyselden/babel,hzoo/babel,existentialism/babel,claudiopro/babel,kaicataldo/babel,existentialism/babel,jridgewell/babel,guybedford/babel,chicoxyzzy/babel,babel/babylon,vadzim/babel,vadzim/babel,maurobringolf/babel,kaicataldo/babel,Skillupco/babel,shuhei/babel,kellyselden/babel,claudiopro/babel,chicoxyzzy/babel,hzoo/babel,maurobringolf/babel,PolymerLabs/babel,samwgoldman/babel,existentialism/babel,jridgewell/babel,kaicataldo/babel,cbishopvelti/babylon,PolymerLabs/babel,babel/babel,Skillupco/babel,claudiopro/babel,guybedford/babel,guybedford/babel,hzoo/babel,hulkish/babel,maurobringolf/babel