Fix python test suites
Fix fstest/model.py 'compile' issues
Add __init__.py to test packages
Removing post-argparse invalidated tests

The move to argparse made many of the clitests unnecessary
since we no longer have our own `Arguments` class, or use
the `_likes()` method.
Fix self.ctx.OMERODIR usage and db.py test

The ctx field for plugins was making undue use of the
OMERODIR global variable. These have been replaced by
a call to `_cwd(None)` which internally uses `self.dir`
which is usually initialized with `OMERODIR`. This makes
it possible to "re-home" a test.

With this change and the minor fixes to clitest/db.py
all of db.py is now passing.
Fixing or removing other broken Python unit tests
Lowering logging to WARN for the unit tests