Conflicts:
	lms/djangoapps/courseware/grades.py

Make location into a named tuple, and use it more as a first class entity, rather than URL for identifying content

These changes make xml import into the cms use XModuleDescriptors

Course settings is in json, not python

Make user profiles work again after the switch to an XMLModuleStore. Staff user histograms are still broken

Begin using a Keystore for XML parsing. Still broken: sequence icons, custom tags, problems, video js

Move the resources_fs abstraction into the primary DescriptorSystem, as it is needed for more than just XMLParsing