Fix for date validation error TIM-575
Add uniqueness constraints for student training models; check for integrity errors
Merge pull request #336 from edx/will/uniqueness-and-integrity

Uniqueness constraints for student training
Make submission_uuid in StudentTrainingWorkflow unique
Merge pull request #335 from edx/will/tim-575

Fix for date validation error TIM-575
Merge pull request #337 from edx/will/one-more-uniqueness-constraint

Make submission_uuid in StudentTrainingWorkflow unique
Fix for TIM-572
Merge pull request #334 from edx/will/multiple-objects-error

Fix for TIM-572
Refactor JavaScript so self- and peer-assessment use OpenAssessment.Rubric
Merge pull request #338 from edx/will/refactor-rubric-javascript

JS rubric refactor
Integrate the student training API with the XBlock.
Adding the Student Training UI