LUN-945: Fix malformed feeds pickling error.

The cache backend throws an exception when pickling the feed object.
In the default context, the feed parser is permissive and returns
partially parsed feeds. It also adds a bozo_exception in the returned
parsed feed that can't be pickled leading to the render error.

Updates
- Don't return bozo feeds
- Add tests
LUN-945: Add tests for handling bozo feeds.
LUN-945: PEP8 updates.
LUN-945: Switch from nose to django-nose.

Move test_settings.py and test_urls.py inside package.
LUN-945: Remove unnecesary 'parse' dependency.
Merge pull request #1 from pbs/LUN-945

Lun 945