Added some functions not available previous to cordova 6
Added some functions not available previous to cordova 6

danielpassos/aerogear-cordova-push,aerogear/aerogear-cordova-push,aerogear/aerogear-cordova-push,danielpassos/aerogear-cordova-push,danielpassos/aerogear-cordova-push,aerogear/aerogear-cordova-push,aerogear/aerogear-cordova-push,danielpassos/aerogear-cordova-push