Make sure Ella works with correct timezone in URL

Fixes #150
For compatibility with memcached, make sure there are no spaces in cache keys
nosetests, travis django versions updated
Avoid urls.defaults deprecation warnings
Support django 1.5's custom user model

Fixes #152
Documentation fixes (a lot of whitespace cleanup)
Updated app_data documentation
Merge pull request #156 from naro/master

Documentation updates.
Utility for serialization of dictionaries/kwargs as cache parameter.
Removing the dict_key function, it has no place in ella.

This reverts commit d05a750b7044cd69e407969076fd5eb21de2156d.
Fix django<1.5 compatibility when importing urls stuff.
Typo fix
Fix publishable not being removed from redis listings if marked as not published *BEFORE* publishing should occur.
Date not timezoned by accident.
Merge branch 'master' into rediswrapper
Even though publishable is not published, we should still return right publishable subclass from object detail.
Merge branch 'master' into rediswrapper