Webcam Settings modal for choosing a webcam

Merge v20 to master nov14

Throwing a toast notification when there is a getUserMedia error on switching between webcams in the preview.

Fix issue: Meeting doesn't end when last user leaves

 - the client to server rtt message is always updating the meeting activity. This prevents the meeting
   from ending due to inactivity.

Handle iframe toggle recording and toggle self muting

Fix dropdown menus not closing in FireFox

Remove ACL from client

Change the method permissions for moderator

Make sure Travis CI doesn't fail when command doesn't produce output for too long

Remove visible recording label

Add meteor disconnect

Add start, stop and publish a poll for Presenter

Stopping the tracks to avoid fetching two cameras at the same time + Making the constraints less restricted