#147 promotion of student to staff with dialog and confirmation
removed footer from dialog
#147 deputy can promote student to deputy
Merge branch 'develop-ja-aquire-role' of https://github.com/tkowark/hpi-hiwi-portal into develop-ja-aquire-role
#147 removed deputy Role and replaced it with helper method
#147 unit tests red for current user is admin
as an admin I can now make students to admins, deputies and student assistants
#147 fixed unit test and added query function to undisplay drop down for chair when admin selected
extracted javascript into separate file

added comments to students.js
Merge remote-tracking branch 'origin/develop-ja' into develop-ja-aquire-role

Conflicts:
	app/assets/stylesheets/students.css.scss
	app/views/students/index.html.erb
	config/locales/views/students/de.yml
	config/locales/views/students/en.yml
	spec/features/students_spec.rb
	spec/views/students/index.html.erb_spec.rb
removed tabs
#147 adapted Research Assistant role to staff