Group things so that the RTD theme TOC will be more helpful.
Some expansion of the Submissions Models docs.
Fix sure lib at 1.2.3 because new version is broken.
More mature error handling around API calls

* Catches SubmissionErrors and sends pass/fail information back to user
  via javascript hidden div.
* Renamed everything from _compose* to just _*
* CSS and js cleanups to make ongoing work less painful (I hope)
Adding a few tests for the Open Assessment XBlock
Add XBlock and xblock-sdk dependencies separately (latter has workbench and sample XBlocks)
Fix django at 1.4.8 because of version conflicts with some dependency.
Make edx-tim install itself so that the XBlock registers.
Quick commit in case we get snowed in
Updating the API and tests.