Changes  "browser is too old message" error message as it's not always related to the browser version.
Does not reload the page when "focus left MUC" event is generated after we have left the MUC intentionally.
Optionally automatically mutes the local video if it is not in any "last N".
Renames a variable/field for the purposes of clarity.
Fixes active speaker avatar and active speaker audio level missmatch.
Modifies default avatar image.
Merge branch 'master' into send_html