Make specific fields on specific TicketTypes editable.
Validation and UI for editable fields
I18n for editable fields.
Update Django to latest patch level

https://www.djangoproject.com/weblog/2014/apr/21/security/
Merge branch 'develop' into fix/ticket106

Conflicts:
	pyconde/locale/de/LC_MESSAGES/django.po
Merge branch 'develop' into feature/schedule-plugin