On every media page there's a comment counter in an

.. raw:: html

   <h3> 
   
element. But if there's only a single comment, it should say
"comment" instead of "comments".

Talked to Brett, turns out my concerns about over-scope of copyleft
in javascript w/ AGPL was wrong, so we should switch our JS
licensing back from LGPL->AGPL.

Not that we have any JS really as I'm writing this ticket ;)

Currently if you try to upload a file for a media type that isn't
handled / isn't currently registered, you get the 500 error page
and in the traceback get:

::

    File '/home/cwebber/devel/mediagoblin/mediagoblin/app.py', line 171 in __call__
      response = controller(request)
    File '/home/cwebber/devel/mediagoblin/mediagoblin/decorators.py', line 50 in new_controller_func
      return controller(request, *args, **kwargs)
    File '/home/cwebber/devel/mediagoblin/mediagoblin/submit/views.py', line 53 in submit_start
      media_type, media_manager = get_media_type_and_manager(filename)
    TypeError: 'NoneType' object is not iterable

This isn't helpful; we should give an error page yes, but one with
useful information that says "sorry, we couldn't recognize that
media type, it might not be supported or not enabled for this
site", or something.

This is a semi-bitesized task.