fix(googlemaps): moveCamera and animateCamera now return a Promise
fix(googlemaps): moveCamera and animateCamera now return a Promise

closes #511

klirix/ionic-native,ramonornela/ionic-native,driftyco/ionic-native,ramonornela/ionic-native,ramonornela/ionic-native,klirix/ionic-native,driftyco/ionic-native,xueron/ionic-native,driftyco/ionic-native,xueron/ionic-native,xueron/ionic-native,ramonornela/ionic-native,xueron/ionic-native,klirix/ionic-native