Explicitly list fields when defining form from model.

This only changes one test (`` test_richtext_widget``), but here's a
short article that may explain why ``fields`` or ``exclude`` becomes
mandatory argument to ``modelform_factory`` and why you actually may
want to explicitly list fields to be available in forms:
http://blog.mhartl.com/2008/09/21/mass-assignment-in-rails-applications/
Let sqlite configuration not contain a ``NAME`` at all (as with some settings environments).
List form fields (as recommended) to preserve compatibility with 1.5.

The "__all__" shortcut must be past-1.6 only.
Fixed ``test_login_required``  when run without ``mezzanine.accounts``.

Note 1: Always testing both scenerios no matter what's in the settings
would be thorough, but without something like the 1.7+ ``modify_settings``
it turns out ugly. It would be better to run the whole suite with and
without some optional apps.

Note 2: This test passes when run through ``runtests``, but it cheats
by forcing ``mezzanine.accounts`` into installed apps ;-)
Merge
Merge