Implement next generation modulestore

A new modulestore backed by mongo that changes the data format to
facilitate easy versioning, sharing content between courses, and fast
lookup of course structure and Scope.settings data.

Conflicts:
	cms/djangoapps/contentstore/tests/test_contentstore.py
Make tests not msec time sensitive
Ensure kvs up-to-date if code accessing it.
Move default set_many impl to xblock
Add feature showing current score next to problem title
Resolve issues with persistence and sequential bar
Attempt to fix video test
Fixed two other tests
Merge pull request #418 from edx/renzo/in-context-progress

Renzo/in context progress
Disabled test failing due to bug in Studio
Merge pull request #444 from edx/will/fix-acceptance-tests

Will/fix acceptance tests
PEP8 and Pylint fixes
Merge pull request #271 from edx/dhm/next-gen-modulestore

Next gen modulestore
tweaks
Merge branch 'master' into ihoover/feature_flag_auto_auth
comment tweaks
working under cms too
resolve conflicts