Fixed problems with branch feature/16449

A bunch of files from the branch that weren't necessary had been merged, and models.py wasn't fixed. It still had the
differences between the branches marked out.
Changed the upload_to field in models.py to 'images'
Fix failing tests

Story, Product, and Image tests needed to test for the inclusion of
their relationships after those relationships were added.

For the Vendor model, at some point the 'id' field got accidentally
removed from the test. My guess is that it was in a merge conflict --
exactly what these tests were designed to prevent.
Add human-readable __unicode__ functions to models
Update __unicode__ functions, add tests