Added rough grading queue UI
Revert modification of current_user
Set half of the deliverables to be ungraded
Implement graded filter for deliverables
Implement graded filter for deliverables
Merge branch 'grading_queue_ui' of github.com:Gonghan/whiteboard into grading_queue_ui

Conflicts:
	app/views/deliverables/_deliverable_listing_professor.html.erb
Merge branch 'master' into grading_queue_ui

Conflicts:
	db/schema.rb
Added capybara-webkit
Merge branch 'grading_queue_ui' into staged

Conflicts:
	app/controllers/application_controller.rb
	app/views/deliverables/_deliverable_listing_professor.html.erb