Expose error state to proctoring rest API implementers

Merge pull request #508 from edx/matthugs/expose-proctoring-error-state

Expose error state to proctoring rest API implementers

1.5.5 Release

Merge pull request #511 from edx/matthugs/add-reviewed_by

Add reviewed_by field to API

Update Instructions page presentation

1.5.3

Merge pull request #506 from edx/matthugs/proctortrack-specific-copy-…

1.5.2 Release

Prevents multiple proctored exam sessions from being created

1.5.1 Release

Fixes saving of reviews in Django admin

1.5.0 Release

This major release refactors edx-proctoring to be a pluggable Django app and allows third-party backend proctoring providers to be dynamically enabled.

Pre release 1.5.0rc7

Merge pull request #495 from edx/dcs/config-perm

Check for file permissions

1.5.0rc6: Add configurations for proctored exam ping functionality

At the proctoring provider level, this allows us to
1) specify different intervals for pinging via configuration changes
2) allow ping failures to continue in emergency conditions via waffle

Pre release 1.5.0rc5

Fixes uglifyJS parsing errors

Pre release 1.5.0rc4

Merge pull request #489 from edx/dcs/review-link

Include a direct link to the review in support tickets