Working prototype implementation.
Add url key to metadata.
Added a readme.
Turn down arrows into up arrows.
Message tray now pops above the panel.
v3
Fix message tray in full screen.
Re-position the panel when its size is changed.

Some shell themes like Faience modify the height of the panel. When that happens
we have to reposition the panel so it sticks to the bottom edge of the screen.
v4
Remove version entry, which only serves to confuse.
Rename panel's name in <C-A-Tab> popup.

Its displayed as 'Top Bar', the extension now changes it to 'Bottom Bar'.
Open popups from panel with up arrow.
editing nano config