correcting visual layout of assessment feedback title/collapse and expand UI
Merge pull request #241 from edx/talbs/fix-TIM-408

FIX - TIM-408
correcting font-weight of staff-info title
Merge pull request #242 from edx/talbs/fix-staffinfo-typography

FIX - Staff Info UI Title Display
proofing message UI:
* aligning text to be left-justified
* adjusting color of paragraph copy to inherit from parent
* moving all message styling to _system-feedback.scss partial
Merge pull request #240 from edx/talbs/fix-inline-errors

FIX - Inline Error Message Display
Fix TIM-381: Invisible Self Assessment errors

* Corrects bad div class
* Adds tests to catch this in future
Merge pull request #244 from edx/jrbl/381-self_assessment_errors_invisible

Fix TIM-381: Invisible Self Assessment errors
Updating the Assessment Models
Updating over grading query to be more performant, and select a random submission
Hide formatted due date in submission if it's not provided
Merge pull request #228 from edx/sanchez/update_peer_workflow_timestamps

Updating the Assessment Models
Merge pull request #246 from edx/will/fix-due-date-text

Hide formatted due date in submission if it's not provided
Add missing view-level tests