Fixing dependency system for javascriptresponses. In particular, adding a location for node-only packages (that are never sent to the client) in lms/lib/node_modules and adding lms/static/js, lms/static/coffee/* to the NODE_PATH, along with the course's data directory.

Adding javascriptresponse. This responsetype is a framework for problems that are entirely controlled by javascript and graded by Node.js on the server.