Fixing BASE_DIR wrt settings being a directory.
Re-adding the main templates directory setting.
Removing custom testrunner.

Looks like Django 1.7 is more sensible with default testing behaviour and
doesn't test itself upon `./manage.py test` - hooray! So a custom testrunner is
no longer needed (and the way it was done is now deprecated in 1.7, anyway.)
Updating (and fixing) functional tests somewhat.