models.py was getting too huge and unmaintainable. In order to keep

things sane, it has been split up into one file per class.
This is more of an implementation detail, as callers are welcome to

continue importing from reviewboard.reviews.models. Django itself only

looks in this module for models anyway.
The code is mostly left unchanged, though there are a few changes:


To resolve circular dependencies, many ModelName.DoesNotExist

  exceptions have been replaced with ObjectDoesNotExist, and

  some imports were added to functions (at most one per file though,

  and only in a couple files).


Some old docstrings have been fixed up to have a one-line summary.


Added app_label = "reviews" to a much of Meta classes. This is

  required to tell Django that it's in the "reviews" module.

Unit tests pass.
Loaded a review request. Created a comment and published the review.

Replied to the comment. Basic functionality all seems to work.