Fix #101 - Make tickets assignable to other users.
Various fixes related to #101.
Less fuzz ...
Fix #94 - Order sponsors by level and date added
Prevent re-assigning of tickets.
Simplify description about listed tickets
Visually align the assignment link to the ticket link it belongs to
Merge branch 'develop' into feature/ticket-owners

Conflicts:
	pyconde/locale/de/LC_MESSAGES/django.po
Merge pull request #108 from EuroPython/feature/ticket-owners

Fix #101 - Make tickets assignable to other users.
Merge pull request #110 from DasIch/deterministic-sponsor-order

Fix #94 - Order sponsors by level and date added