Fixes #68

Update JavaScript so it orders pins, Fixes #69

Rewritten API to handle creating pins for both urls
and previously-uploaded images. Added some tests for it.

Generate thumbnail and standard image on request, and use
http://github.com/mirumee/django-images for generating them. Also,
remove the CreatePin page as pin creation is going to be done
in JavaScript. Create UploadImage view for uploading images from
computer.

REST API should be used to delete pins anyway, so remove the old code
that is not being used.

I have a gut feeling that we could refactor some code out of this method, but for now I'll just clean it up a bit.

There has been some refactoring going on in the pinry.pins.models module.
The upload_to code has been refactored into its own function, images
have been moved to their own models - otherwise the number of fields
in the Pin model would skyrocket. Also ModelManagers have been written
to move image fetching and generating outside of models.

Tastypie's ModelResource makes use of the underlying Model class to figure out its fields. It obviously
breaks when there is inconsistency with models, which is rather rare, but possible to accomplish (which I've
proven with the previous commit).

-e should be used only with repositories apparently

The previous commit uses url syntax from Django 1.5, which is incompatible with earlier versions. Bump the Django version
and use the stable/1.5.x git branch until it's officially released.

A version of url introduced in Django 1.3 requires the view argument to be quoted. This change
has taken effect in Django 1.5 so the code needs updating to work with it.

Update README.md