Remove dead code

(found by looking for https://www.djangoproject.com/weblog/2014/mar/22/strip-tags-advisory/)
Fix #102 - Show canceled purchases in profile area

Canceled purchases are now shown in the profile area, with a warning and
without the button to resend invoices.
Fix #101 - Make tickets assignable to other users.
Add translation for canceled purchase message
Various fixes related to #101.
Less fuzz ...
Merge pull request #107 from DasIch/show-canceled

Fix #102 - Show canceled purchases in profile area
Fixed #73 -- don't escape quotation marks in comment mail
Fix #94 - Order sponsors by level and date added
Prevent re-assigning of tickets.
Merge pull request #109 from EuroPython/fix/ticket73

Fixed #73 -- don't escape quotation marks in comment mail
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
Reorganized split of ticket models.
Merge remote-tracking branch 'origin/develop' into feature/extended-tickets
Update pytz
Merged changes form development and fixed them.