Improves Controller and Adapter relationship

- Controllers that have adapters are AdaptableControllers
- AdaptableController is responsible to instantiate the proper adapter if needed (string, function or BaseAdapter)
- BaseAdapter is the base class for adapters, allows skipping when passed directly to the controller

spec/OneSignalPushAdapter.spec.js

@@ -227,7 +227,8 @@ describe('OneSignalPushAdapter', () => {
 
   function makeDevice(deviceToken, appIdentifier) {
     return {
-      deviceToken: deviceToken
+      deviceToken: deviceToken,
+      appIdentifier: appIdentifier
     };
   }