feat(AgmMap): know when map is ready
feat(AgmMap): know when map is ready

You can now listen to the new mapReady output
to know when the map is initialized.

Closes #740
Closes #972

caravancoop/angular2-google-maps,pSuwalski/angular-google-maps,pSuwalski/angular-google-maps,pSuwalski/angular-google-maps,SebastianM/angular2-google-maps,caravancoop/angular2-google-maps,tobper/angular2-google-maps,tobper/angular2-google-maps,SebastianM/angular2-google-maps,SebastianM/angular-google-maps,SebastianM/angular2-google-maps,tobper/angular2-google-maps,caravancoop/angular2-google-maps,SebastianM/angular-google-maps