Removed the Cordova.addConstructor wrapper, as this is deprecated

See http://stackoverflow.com/questions/10587398/cordova-custom-plugin-structure-w-o-callbacks and http://stackoverflow.com/questions/16082637/alternative-to-cordova-addconstructor
DroidGap was replaced with CordovaActivity (about 6 months ago)

See https://github.com/apache/cordova-android/commit/48b8c69ba0ebe1d093ef2c6721d007178f59ef8b
Merge pull request #1 from jrstarke/master

Removed the Cordova.addConstructor wrapper, replaced DroidGap