Add Exam Dates Feature

Now you can list and manange exam dates.

Conflicts:
	app/views/exam_dates/_form.html.slim
	features/exam_dates.feature
	features/step_definitions/vvz_steps.rb
	script/test
	script/test-server
	spec/controllers/exam_calendars_controller_spec.rb
	spec/controllers/exam_dates_controller_spec.rb
	spec/requests/exam_calendars_spec.rb
	spec/requests/exam_dates_spec.rb
	spec/routing/exam_calendars_routing_spec.rb
	spec/routing/exam_dates_routing_spec.rb
	spec/views/exam_calendars/index.html.slim_spec.rb
	spec/views/exam_calendars/show.html.slim_spec.rb
	spec/views/exam_dates/edit.html.slim_spec.rb
	spec/views/exam_dates/index.html.slim_spec.rb
	spec/views/exam_dates/new.html.slim_spec.rb
	spec/views/exam_dates/show.html.slim_spec.rb