Updates Django for security, bug fixes
Update filebrowser to supported version
Update debug-toolbar to supported version
Downgrade filebrowser to last compatible version

Corrects 97217eb5.
Adds missing uses of @functools.wraps()

In Django security release 1.4.11, reverse() stopped supporting paths
that weren't already loaded in a urlconf. The
RegexURLResolver._populate() method takes care of recursively inspecting
the root urlconf and maintaining a set _callback_strs of all paths used
in the urlconf that are allowed to be used in calls to reverse().

When a callable view function object is passed to the urlconf (as
opposed to a dotted path string), _populate() inspects the object to
determine the dotted path string from its module, class, and function
names. When the callable view function is decorated with a wrapper that
does not use @functools.wraps(), this information is lost. The result is
that legitimate calls to reverse() and {% url %} are no longer allowed.

This was causing an error in the admin panel. Specifically, the call to
{% url esp.themes.views.landing %}, since landing() is decorated by
@admin_required(), which was missing the use of @functools.wraps().

The fix is to make sure to always use @functools.wraps() when defining
decorators, especially when those decorators will be decorating view
functions.

Another possible fix would have been to use the wrapt package. See
Github issue #1307.
Forks filebrowser to fix tests

We can't downgrade filebrowser, because <3.5.7 have tests that fail on
django>=1.4.14. Instead, fork 3.5.7 with the compatibility issue
reverted, until they fix it.

An issue has been filed for the compatibility issue. See
<https://github.com/sehmaschine/django-filebrowser/issues/241>.

See also the revert made in the fork, at
<https://github.com/learning-unlimited/django-filebrowser/commit/4557e6a6>.

Corrects add9c22d.
Merge pull request #1304 from learning-unlimited/django-security

Updates Django for security, bug fixes