Getting draft split_test_module instances to import/export.

STUD-327
Merge pull request #4491 from edx/christina/export-split

Getting draft split_test_module instances to import/export.
Release notes for 7-23-2014
Merge pull request #4531 from edx/sylvia/docs/relnotes_7_23

Release notes for 7-23-2014
Make overriding branch settings thread-safe LMS-11125