admin student acitvation and translations
student and employer activation controller actions
activated batches
employer and student activation buttons
hiding not activated students and employers
Emails to the administration for activation
Account settings with change password functionality
restricting access rights for deactivated students and employers/staff
Merge branch 'develop' into feature/activation

Conflicts:
	app/controllers/students_controller.rb
	app/models/ability.rb
	app/views/students/_profile_fields.html.erb
deactivated test subjects
Merge pull request #363 from hpi-swt2/feature/activation

Feature/activation
Merge remote-tracking branch 'origin/develop' into new-homepage

Conflicts:
	app/views/employers/index.html.erb
	app/views/employers/show.html.erb
	app/views/layouts/application.html.erb