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.
Initial fix to make a POST request when deleting a facility.
Adds hipchat to travis notifications.
Updates email notifications in travis.
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
Fixes data export for headless zones.
Fixes linting.
Fixes data export on distributed server.
Merge branch 'nalanda-rct3' of github.com:learningequality/ka-lite into nalanda-rct3
Merge branch 'release-0.12.0' into hotfix/2198-Deleting-a-facility-should-NOT-use-a-GET-request
Add tastypie package.