Merge pull request #2281 from learningequality/release-0.12.0

Release 0.12.3
metadata for 0.12.3
Merge branch 'release-0.12.0'
Merge pull request #2308 from learningequality/release-0.12.0

Release 0.12.5
Merge pull request #2351 from learningequality/release-0.12.0

Release 0.12.6
Add `hacks_for_phantomjs()` method.
Merge pull request #2373 from mrpau/hotfix/add_phantomjs_hacks

Add `hacks_for_phantomjs()` method for `release-0.12.0` branch.
Bam, add exercise log export option
Adds hipchat to travis notifications.
Merge pull request #2379 from learningequality/exerciselogcsv

Bam, add exercise log export option
Updates email notifications in travis.
Revert "use logging rather than writing to stdout directly" for collectstatic

This reverts commit 239fa61bd5bf577503be9b90830dd466194cfb55.
Added Test facility for A/B testing.
Merge branch 'nalanda-rct3' of github.com:learningequality/ka-lite into nalanda-rct3
Adds new encrypted email for Travis notification (hopefully works this time).
Uses .get instead of keying directly into UNIT_EXERCISES dict.
Prevents exercise api endpoint from breaking.
Gives up on trying to encrypt email for Travis. BAH!
Merge branch 'master' into release-0.12.0
Merge branch 'release-0.12.0' into nalanda-rct3

Conflicts:
	kalite/testing/browser.py
Fix knowledgemap_topics loader to index into ID