Ticket #136

changed the question api to not required additional content or
attachment
Implemented link to drop user from the course on the Manage Users

screen.
Moved Activity screen to Question Screen

It is now found in a tab that is only visible to TAs and Instructors
- question select field has been removed
- sorting has been implemented for most of the columns
- filtering by groups and students have been implemented

Note: the tab is being hidden with ng-show instead of ng-if. If
ng-if is used the tab will not work.