Add event comment posting to API.
Added user's full name into comment saving.
Creating new talk comment returns comment URI.
Fixes JOINDIN-332.
Return location header with the new comment URI.
more robust test for an empty twitter username
Merge remote-tracking branch 'lornajane/attending-tests'
Stopped the tests from failing if the Twitter username is null in the API response
Merge remote-tracking branch 'richsage/post-event-comment'
Merge remote-tracking branch 'richsage/JOINDIN-332-comment-uri'
Merge remote-tracking branch 'magicmonkey/fix_twitter_test'
sorting the talks collection by date/time