715 Dashboard changes
Copied some files from E707 in duplicate branch. Will be used to merge
Integrated E707 with E715 with some refactoring
Integrated E707 with E715. Auto-expand courses' assignments
Changed score cache with updated functions to find the correct statistics
Added a test for 715_check_class_statistics
Capybara-selenium test for auto-expand assg for courses
Deleted empty test spec
Merge branch '715branch' into OSS-E911
Fixed error in spec
Merge branch 'e911'

Conflicts:
	app/controllers/grades_controller.rb
	app/controllers/tree_display_controller.rb
	app/models/signupsheet.rb
	app/views/grades/view_my_scores.html.erb
	app/views/tree_display/_row_header.html.erb
	db/schema.rb
	log/test.log