Course staff can see counts.
Add UI styling for course staff, including collapse/expand.
Cache student item when retrieving submission and student item.
Protect against invalid cache key exceptions.
Update test suite to clear cache between tests.
Add composite index for AssessmentWorkflow student item fields
Merge pull request #222 from edx/will/staff-counts-workflow

Course staff can see counts
Add event and INFO level logging.

This introduces a few features:
* INFO level logging on common events like creating or fetching
  submissions and assessments.
* Parallel event logging for the same.
* Creates a local logs/ directory for development.

For the most part, we rely on XBlock's publish() mechanism to emit
event data. However, because scoring is done at the API layer in a way
that is not directly visible to the OpenAssesmentBlock, we're logging
that event separately with a hacky solution that dynamically loads an
emit function based on a configuration value. This is a stopgap
measure until we can start using the edX analytics API (which is still
in testing).

TIM-260, TIM-378
Merge pull request #229 from edx/ormsbee/analytics_events

Add event and INFO level logging.
Updating Rubric Validation to allow Criteria and CriterionOption name changes

No longer supports re-ordering of options and criteria, but allows name change.
Show item_id (location) in Course Staff Debug section.

It's cumbersome to get otherwise, and staff will want it for state
resetting (if it comes to that).
Merge pull request #230 from edx/ormsbee/staff_debug_item_id

Show item_id (location) in Course Staff Debug section.
Change config key from EDX_TIM to EDX_ORA2
Hide course staff debug info in studio preview
Merge pull request #233 from edx/will/hide-staff-debug-in-studio-preview

Hide course staff debug info in studio preview
Merge pull request #234 from edx/ormsbee/conf_name

Change config key from EDX_TIM to EDX_ORA2
Validation check for duplicate criteria and options
Merge pull request #232 from edx/will/no-duplicate-criteria

Validation check for duplicate criteria and options
Merge pull request #231 from edx/sanchez/TIM-403-XML-Validation

Allow Criteria and CriterionOption name changes
Updating the Assessment Models