Backport release

from Stanford-Online/release
into Stanford-Online/master
Fix json_update_videos()
      commit (1f5c95b) to transcript_utils.py changed the sig of download_youtube_subs
    from def download_youtube_subs(youtube_subs, item, settings):
    to def download_youtube_subs(youtube_id, video_descriptor, settings):

    hence taking a video id instead of a dict.

    This broke the download captions feature from the utilities page.
make unit tests respect mongo port/host settings (with default)

settings are read in from environment variable
Merge pull request #104 from Stanford-Online/jbau/master-parallel-tests

make unit tests respect mongo port/host settings (with default)
Merge pull request #106 from Stanford-Online/dcadams/fix_vid_transcript_dl

Fix json_update_videos()
pick up new ora2 (7/21 -> 8/08)
Merge branch 'rc' into release

* rc:
  pick up new ora2 (7/21 -> 8/08)
  make unit tests respect mongo port/host settings (with default)
  Fix json_update_videos()       commit (1f5c95b) to transcript_utils.py changed the sig of download_youtube_subs     from def download_youtube_subs(youtube_subs, item, settings):     to def download_youtube_subs(youtube_id, video_descriptor, settings):