fix($state): Fix "Possibly unhandled rejection" by catch()ing the transition promise

Now calling `.catch()` on the transition promise

Closes #3246
Closes #2889

Author: christopherthielen

src/state.js

@@ -1219,6 +1219,7 @@ function $StateProvider(   $urlRouterProvider,   $urlMatcherFactory) {
         return $q.reject(error);
       });
 
+      transition.catch(angular.noop);
       return transition;
     };