Merge branch 'release-0.12.0' into master
Merge pull request #2537 from learningequality/release-0.12.0

Release 0.12.8
metadata for 0.12.8
Merge pull request #2742 from mrpau/hotfix/2271-Export-CSV-data-quality-issues

Hotfix/2271 export csv data quality issues
Revert "Hotfix/2271 export csv data quality issues"
Merge pull request #2747 from learningequality/revert-2742-hotfix/2271-Export-CSV-data-quality-issues

Revert "Hotfix/2271 export csv data quality issues"
Merge remote-tracking branch 'refs/remotes/upstream/master' into release-0.12.0
metadata for 0.12.9
Fix to remove partially watched videos from result of queryset.
Merge pull request #2768 from mrpau/hotfix/2271-Export-CSV-data-quality-issues

Fix to remove partially watched videos from result of queryset.
Make default uuid generation random (uuid4), not based on counter.
Make counter incrementing more atomic, to avoid race conditions.
Move the old version of get_uuid into the new method, for reference.
Merge pull request #2818 from jamalex/fix_uuid_race_conditions

Fix UUID race conditions
decrease query test # of expected queries threshold, because we're
needing less queries now to compute the uuid
metadata for v0.12.10
corrected metadata for v0.12.10
Don't show unit 100 on unit-switching page.
Slight refactor of modal display on unit switching page.
Show loading modal on exam setting page.