Added django debug toolbar configuration

By setting the corresponding environment variable, the django debug
toolbar is loaded. This is very useful for debugging templates and SQL
queries.

Additionally, two unrelated PEP8 violations have been fixed.
Enabled timezone support in Django.

This commit enables USE_TZ in settings.py. Additionally, the pytz
library has been added to requirements.txt.
Epoch fields now return timezone-aware datetimes.

This is done by explicitly marking datetimes returned from an
EpochField as UTC dates. In the templates, Django automatically
converts aware dates to localtime.
Fixed tests by always using aware datetimes
Fixed old usages of native datetimes
Updated copyright line.

The copyright now says "© 2013–2014 HSR University of Applied Sciences
Rapperswil & contributors".

The second year will always be up to date as it's dynamically computed.
Added dajax and select2 to support typeahead autocompletion

The query in ajax.py must be rewritten, currently it's very slow.
(tnc-ba/strongTNC#28)

Conflicts:
	tncapp/templates/tncapp/base.html
	tncapp/templates/tncapp/policies.html
	tncapp/urls.py
Splitted line to fit into pep8 max length
Another pep8 problem fixed