Merge pull request #125 from jorr/feature/global-js-runtime

Refactor JavaScript runtime into a global object
Pass url suffix to handlers explicitly

Also extend handler_url to accept both an explicit path suffix and query
string, so that Runtimes have more control over the full url that they
return.
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 #123 from cpennington/handler-suffix

Pass the url suffix to handler functions explicitly
Merge pull request #127 from cpennington/file-like-webob-request

Set a file-like object on the webob request
Introduce Runtime.resources_url() to provide url for static resources
Merge pull request #126 from edx/jorr/feature/runtime-resources-path

Introduce a method in Runtime to provide url for static resources