added completionHandler
added completionHandler

ceisinger/cordova-plugin-firebase,podmaxs/cordova-plugin-firebase-bigapp,arnesson/cordova-plugin-firebase,jluisfg/cordova-plugin-firebase_comexmovil,t-co-in/shapes-free,arnesson/cordova-plugin-firebase,ceisinger/cordova-plugin-firebase,krtek1979/cordova-plugin-firebase,jluisfg/cordova-plugin-firebase_lasus,ceisinger/cordova-plugin-firebase,tdachev/cordova-plugin-firebase,Vying/cordova-plugin-firebase,DigitalsunrayMedia/cordova-plugin-firebase,arnesson/cordova-plugin-firebase,nieok/cordova-plugin-firebase,jluisfg/cordova-plugin-firebase_ppgnews,canado/cordova-plugin-firebase,canado/cordova-plugin-firebase,jluisfg/cordova-plugin-firebase_ppgnews,nieok/cordova-plugin-firebase,t-co-in/shapes-paid-US,ceisinger/cordova-plugin-firebase,Vying/cordova-plugin-firebase,tdachev/cordova-plugin-firebase,podmaxs/cordova-plugin-firebase-bigapp,DigitalsunrayMedia/cordova-plugin-firebase,tdachev/cordova-plugin-firebase,DigitalsunrayMedia/cordova-plugin-firebase,nieok/cordova-plugin-firebase,jluisfg/cordova-plugin-firebase_lasus,jluisfg/cordova-plugin-firebase_comexmovil,canado/cordova-plugin-firebase,krtek1979/cordova-plugin-firebase,Vying/cordova-plugin-firebase,arnesson/cordova-plugin-firebase,t-co-in/shapes-free,t-co-in/shapes-paid-US