Miscellaneous bug fixes

This release removes the debugging information useful throughout the UAT phase of the 4.0.0 release candidacy. A final release was made that included the debugging information which worked perfectly fine, but yet again Mozilla had something to complain about.

It also fixes an issue where the extension would fail to run after trying to query a non-existent container. This would happen if you land on the home page. Moving on to a mix from there would never yield a tracklist unless you refresh the page.