fix(clientSideScripts): waitForAngular now also waits on manually bootst...

...rapped applications.

With some manual bootstrapped applications the client-side call to waitForAngular threw an error because
angular.element(el).injector() did not exists. For these applications the injector can be gotten with
angular.bootstrap().get('$browser'). This fix also returns a more readable error-message when $browser cannot be determined by protractor.