HTML5 Dropdown - fixed warnings and added style

Add colour notification to caption tab when locale is switched

Invite participants to existing breakout rooms

Switch moderator back to the main audio conference when close all breakout rooms button is clicked

[HTML5] Fix SPACE/ENTER behavior

[HTML5] Refactor of Modal and Dropdown components

Improve detection of corrupt videos via ffprobe

* upstream/master: (30 commits)
  User in not redirected automatically to the logoutURL.
  Fix errors in recording scripts.
  - fix issue where client cannot join using rtmpt
  Remove a few matterhorn references that were missed.
  Update the Gemfile.lock file to match gem changes
  Improve wave length guessing
  Remove a bunch of unused/old audio processing code.
  Drop streamio-ffmpeg from required gems
  Drop old/broken matterhorn script, and old video processing code.
  fix exception with cc localeCode vs. code
  - do not recycle http connection. Use a fresh one for each request to prevent exception    when reusing old connection.
  - comment out record option for breakout rooms pending further testing.
  - change jws failed to start timeout from 60s to 90s. Sometimes it takes about    30s to download the libs especially for those far from the server or those with    slow connection.
  - custom poll was sent to the wrong actor. Route it to the correct meeting actor.
  - propagate meeting metadata from parent to breakout room
  add a fourth help image for mac screenshare
  add property to closed caption transcript model for the locale code
  Added more explanation for Mac FireFox in screenshare-help.html
  - do not display the "Record" label.
  Hide breakout rooms checkbox.
  ...

User in not redirected automatically to the logoutURL

Fix errors in recording scripts.

Logger was apparently imported by the matterhorn stuff ?! so move that
to the main library.

Fix a variable reference in sanity.

 - fix issue where client cannot join using rtmpt

Remove a few matterhorn references that were missed.

Recording cleanup

Instead of assuming that wav files have 44 byte headers (they usually
don't - freeswitch adds some metadata tags), add a super-simple wave
file parser that just finds the offset where the audio data actually
starts.

The sanity check script was using one of the functions; it's been
changed to use a function from the EDL audio code instead.

It's no longer used anywhere in the recording processing, and the one
remaining use in the sanity script can be replaced with a (less buggy!)
function from the video EDL code.

Fix exception with closed caption tab for viewers

 - do not recycle http connection. Use a fresh one for each request t…

   when reusing old connection.