remove displayed raw state

the raw state is obviously seen when we have slow internet connection and it will flashed {{authService.user.username}}, so according to ngBind doc, we should use ng-bing to resolve this issue.
http://docs.angularjs.org/api/ng.directive:ngBind
Merge pull request #4 from muhammadghazali/remove-displayed-raw-state

remove displayed raw state