Added a module of renderers

I haven't plugged these into resources.py yet, but I'm about to.
Made sure field serialization is done through the renderer
Not quite there

I now pick the renderer based on the content type, but there is still one
part missing.  Specifically, I make a distinction between serialization
(which traverses the hierarchy and creates a Python representation) and
rendering which converts the Python representation into text.  I'm
still relying on mimerender to do that last part, I need to fix that.
Close to being able to close the loop on rendering
One thing left, but all tests pass.

This looks pretty solid.  The only issue I see here is making sure we have
the right interaction between mimerender and the content type that a
given renderer intends to return.  Currently, I'm not imposing and
specific hypermedia format, e.g. text/xml, in the tests so this doesn't
cause any problem.  But I need to make a test case with a renderer that
returns XML and/or a flavor of JSON like application/hal+json and make
sure that mimerender handles it correctly.  I suspect this will require
me to make the mimerender functionality extensible.  I'm not sure how
to do that since it is a decorator in the base class and I can't really
affect it (or can I?).
Following the pattern in the mimerender docs for naming the decorator.
Nearly there

I think we'll need to depend on mimerender, but we have to figure out
a way to get it to accept JSON dialects and return the correct
mimetype in the response.  I've added a test, but I haven't yet
configured the application automatically (I need to remove the
manual config of mimerender somehow).

Also, I think the rendering really needs to go with the view, so
I'm going to shift it over I think.
Moved renderer setting to the view side
Decorator gymnastics for the win

This completes everything I wanted to do.  The Renderer classes
now can control what the mimerender function can really handle
on a view by view basis.  I just need to write a test case to show
how it can be used and this should be done.
Added a test case
Extension to specify per-request resource types

This is useful when you have a view to a Document that allows
inheritance because it can use request information to determine
exactly what type of resource is being POSTed or PUT.
Merged first set of authorization changes.
Next manual merge bit
Third manual merge
Cloning QuerySets

I didn't notice before that the QuerySet objects have internal state.
I assumed that each time you applied a filter, a new QuerySet object
was created, but this isn't the case.  So when calling has_read_permission
it is necessary to clone the queryset to avoid side-effects.
Completing the merge of renderers branch
Forgot to inherit from object in Renderer class
Fixed another issue with inheritance
Changes in serialization

Resources are responsible for providing serialized versions of their fields
and Renderers are responsible for serializing the complete object.
Added support for MapField and FileField