added model tests for the validation of birthdates #110
added translations for natural languages #100
Merge branch 'develop-ja' into develop-ja-localize-db
adjusted schema
Merge remote-tracking branch 'origin/develop-ja-bday-validation' into develop-ja

Conflicts:
	spec/models/user_spec.rb
added gem chronic for birthday validation, changed datepicker on students edit page to be 3 selects
added the user profile picture to the menu bar #58
added the folder structure and a missing.png for the chair #108
merged develop into develop-ha

conflicts:
user.rb
user_spec.rb
adapt job_offers form to ui_guidlines, #90, #111
redesigned students show #90, #111
refinement on students show #111, #90
adapt student show to guidelines, #111, #90
ui adaption to julias suggestions #111, #90
removed academic program and semester from view test, since it is removed from the view #111, #90
redesigned job offer detail page, #111
Merge remote-tracking branch 'origin/develop' into develop-ja

Conflicts:
	Gemfile
	Gemfile.lock
	app/controllers/application_controller.rb
	app/controllers/job_offers_controller.rb
	app/controllers/students_controller.rb
	app/controllers/studentsearch_controller.rb
	app/helpers/sessions_helper.rb
	app/models/job_offer.rb
	app/models/user.rb
	app/views/job_offers/show.html.erb
	config/locales/models/job_offer/de.yml
	config/locales/models/job_offer/en.yml
	config/locales/views/job_offers/de.yml
	config/locales/views/job_offers/en.yml
	spec/controllers/chairs_controller_spec.rb
	spec/features/job_offers_spec.rb
	spec/features/students_spec.rb
	spec/features/studentsearches_spec.rb
	spec/models/job_offer_spec.rb
	spec/models/user_spec.rb