Minor cleanup around public RESTful URLs.

STUD-849
Fix 0010 courseware migration
Allow colons in Locator fields.
BLD-474: Allow multiple answers for string response.
Merge pull request #1740 from edx/bug/locator_parse

Allow colons in Locator fields.
Merge pull request #1727 from edx/christina/public

Minor cleanup around public RESTful URLs.
Merge pull request #1698 from edx/anton/multiple-answers-string-response

Allow multiple answers for string response.
Convert tabs to RESTful URL.

STUD-850
Merge pull request #1675 from edx/christina/tab-new

Convert tabs to use RESTful API
Merge pull request #1736 from edx/jbau/fix/cw-migrations

Fix 0010 courseware migration
BLD-530: Fix 500 error in transcripts.
Merge pull request #1739 from edx/alex/fix-transcripts-500-error

Fix 500 error in transcripts.