Added support for authentication against Active Directory subdomains.

This patch enables authentication against specific AD subdomain extracted from
the username. E.g. for configured domain name "example.com" user "north\tom"
will be authenticated as "tom" against "north.example.com".

Testing done:
I have this running fine with multiple AD subdomains configured in my
organization.

Reviewed at https://reviews.reviewboard.org/r/2838/
Update the test suite names for ReviewRequestManager tests.

DbQueryTests had tests named after the old DB query functions we had way
back before introducing ReviewRequestManager. The names and docstrings
were old and outdated. This updates them for the appropriate names,
making it easier to see if they fail, and to introduce new tests.
Update the test suite names for ReviewRequestManager tests.

DbQueryTests had tests named after the old DB query functions we had way
back before introducing ReviewRequestManager. The names and docstrings
were old and outdated. This updates them for the appropriate names,
making it easier to see if they fail, and to introduce new tests.
Merge branch 'release-1.6.x' into release-1.7.x
Extend TestCase to add new fixture and model creation functionality.

Some of TestCase's create_* functions now take additional parameters for
the control of access restrictions and draft management.

It also introduces load_fixtures(), which can be used to add additional
fixtures to a given test.
Merge branch 'release-1.7.x'
Fix the rb-site djblets symlink.

The new Djblets static media support has a new destination for generated
media files. rb-site, though, was still pointing to the old location,
resulting in failed lookups.

We now symlink the proper static location.