This is pre-work for the PDF media type handling which is supposed to show default pdf fallback icons in the beginning.

Please consider merging the branch get_thumb_url from my git repo at ​git://gitorious.org/~spaetz/mediagoblin/spaetz-mediagoblin.git.

Description of my change straight from the commit log:

    Simplify/Robustify the thumbnail URL usage in templates
    
    So far templates required a very complex blurb to simply insert a
    thumbnail URL, exposing much of the internal logic to the template
    designer. In addition, we would fail with an error if for some
    reason the media_files['thumb'] entry was never populated.
    
    This adds the MediaEntry.thumb_url property that template designers
    can simply use. It will do the right thing, either fetching the proper
    thumbnail or hand back a generic icon specified in a media's
    MEDIA_MANAGER as "default_thumb".
    
    Add an image default fallback icon (stolen from Tangos, which are
    Public Domain since version 0.8.90 as I understand) since the one
    we referred to was not existing. Perhaps, a "broken image" icon
    would be better, but I'll leave that to our capable designers.
    
    All templates have been modified to make use of the new thumb_url
    function.

When ernot being an admin all admin pages come up as 404 (not found) addresses. This confused me a lot because I thought things are broken until I realized I am not an administrator.

The task is to return "FORBIDDEN" pages when calling admin pages without necessary permissions.

Currently there is no way to make someone admin but to fudge with SQL directly. It's common practice to set up an admin account after installation, so it's reasonable to auto-admin the first created user. I expect that any admin can then give admin rights to other users via the web UI.

I'd like to have cwebbers input on this before working on this task though :).