Revert "Update opaque-keys library to use block_id for html_id for new keys."
Merge pull request #4964 from edx/revert-4960-split/html_id

Revert "Update opaque-keys library to use block_id for html_id for new k...
Make sure that the currently-set language is the
one that shows on the left sidebar if no language
preference exists.

ECOM-135
Update opaque-keys library to use block_id for html_id for new keys.
Catch more places where get_children was giving us version aware references.
LMS-11237
Merge pull request #4966 from edx/split/html_id

Update opaque-keys library to use block_id for html_id for new keys.
Pin coffee-script version to 1.6.1.
BLD-1226: enable 'delete_inactive_group' test.
Merge pull request #4970 from edx/anton/enable-bok-choy-test

Enable Bok Choy split test.
Add test for at least one group before saving a group configuration
Merge pull request #4959 from edx/diana/set-cur-lang

Make sure that the currently-set language is the one that shows on the left sidebar if no language  preference exists.
Merge pull request #4973 from edx/tim/single-group-is-ok

Update test_group_configuration_validation on single group allowed
Merge pull request #4969 from edx/benp/fix-js-tests

Pin coffee-script version to 1.6.1.

1.6.3 is causing some issues.
login, registration, and dashboard page changes for third-party auth
Facebook auth support.
Add server-side analytics logging for login
Remove client-side analytics logging for login
Remove unnecessary TODO
Fix TODOs
Response to CR
Remove unnecessary javascript