- added "sanitize" gem
- implemented "sanitize_html" to strip all html from a string except stuff from a whitelist
--> this allows us to still use bootsy but work around the security risks
- added custom whitelist to sanitize_html #219
- added test for "sanitize_html" #293
- adjusted standard buttons for bootsy, removing the non-functional image button and adding the view-as-html button
$- added test for 'sanitize_html' #219 \n- adjusted standard buttons for bootsy, removing the non-functional image button and adding the view-as-html button
added test for 'sanitize_html' #219
- changed default bootsy settings to remove the non-functional image button, adding the view-as-html button
added vacant_posts to the permitted parameters in the job_offer controller
Merge branch 'develop-ja' of https://github.com/tkowark/hpi-hiwi-portal into develop-ja
changed default vacant posts value back to 1
Merge remote-tracking branch 'origin/develop' into develop-ja

Conflicts:
	app/controllers/job_offers_controller.rb
	app/views/job_offers/_form.html.erb
	app/views/job_offers/show.html.erb
made denotion modal bootstrapy #301
Job prolonging only for running jobs
some message translations for job offers
a small improvement
enforced cancan for staffcontroller
Locale based date formatting
added end date to view tests job offer
removed unused before filters
cancan for studentscontroller
cancan for applicatons
Merge branch 'develop-ak' of https://github.com/tkowark/hpi-hiwi-portal into develop-ak