Rebase branch 'on-change-callback'
Rebase branch 'on-change-callback'

fbentz/angularfire,yoda-yoda/angularfire,itxd/angularfire,itxd/angularfire,FirebaseExtended/angularfire,cesarmarinhorj/angularfire,yoda-yoda/angularfire,bpietravalle/angularfire,cesarmarinhorj/angularfire,fbentz/angularfire,douglascorrea/angularfire,jamestalmage/angularfire,denisKaranja/angularfire,nbr1ninrsan2/angularfire,douglascorrea/angularfire,denisKaranja/angularfire,bpietravalle/angularfire,jamestalmage/angularfire,FirebaseExtended/angularfire,nbr1ninrsan2/angularfire,FirebaseExtended/angularfire,nbr1ninrsan2/angularfire,cesarmarinhorj/angularfire,jamestalmage/angularfire,itxd/angularfire,yoda-yoda/angularfire,fbentz/angularfire,denisKaranja/angularfire,douglascorrea/angularfire,bpietravalle/angularfire