Add test of django -> webob request conversion
Implement a webob.Request backed by a django request

This lets us provide GET, POST, and body implementations that pull
directly from the django object, so that if the body has already been
read in the django code (for instance, by middleware), the webob request
can still access it (and the POST variables, etc).
Merge pull request #127 from cpennington/file-like-webob-request

Set a file-like object on the webob request