put back the inheritable_metadata list into the XModuleDescriptor class. Also extend the metadata_inheritance test case

add some comments regarding which code can be removed when the 'split mongo module store' work is completed

compute (and cache) a generation of metadata inheritance tree for the course. We can then add that metadata to a newly instantiated xmodule

add exporting of policy.json

fix module staff accesss - by has_access, not by user.is_staff

Better logging, and make view csrf exempt...

Feature/victor/foldit api

  - ops view for the desktop app to talk to
  - xmodule that talks to the foldit model and displays the student's state
  - grading tweak to make grade updates from an external service work:
    - Add an always_recalculate_grades property to XModuleDescriptor.

Firefox doesn't draw the buttons right with -90deg, but will draw it rig...

Feature/valera/video alpha

Firefox doesn't draw the buttons right with -90deg, but will draw it right if no direction is specified.

700x sandbox

allow "rows" attrib of coderesponse textbox to set box height