Fix subtitle download links (#929)

Changed it so instead of sending a Content-Disposition header, we
simply use the filename we want in the URL.  This works better with
non-ascii characters.

Moved the view from the widgets app to the subtitles app.

Cleaned up the widget javascript a bit.

Copied team member code from gh-1046.  I think this code is nicer than
the current stuff and I wanted to use it for the subtitles download
view.
Fixed unittests
update the download tests, add one for vtt
test with the subs downloaded content
Fixed a bunch of issues with the follow buttons

Correctly render Following/Not following on the language page.  Fixed
follow all languages/unfollow all languages on the backend side.
Switch the label to say "Following" when the user clicks follow all
languages.
Switch to the dummy backend on docker dev

This makes emails not fail, which was causing
send_video_comment_notification to also fail.
Link to correct page for comments on languages (#700)
Fixed auth headers when updating task notes (#1111)
Bumping integration repo

This fixes another bug I hit while debugging #1111
Merge branch 'staging' into gh-929
Fixed JS error when switching languages.
Include language name in comment messages
Merge pull request #1132 from pculture/gh-700

Gh 700
Merge pull request #1131 from pculture/gh-929

Gh 929
Merge pull request #1129 from pculture/gh-1111

Gh 1111
Fixed double slash in the comment notification emails
Merge branch 'gh-700' into staging
Added some docker commands to dump/restore the database
Merge branch 'staging' into gh-1080
Setup the current Site object in dbreset.py

Added code that sets the current Site to have the correct domain for
docker dev work.  This makes a few URLs work that wouldn't otherwise.