For Firefox/OpenOffice, right now we have a workaround in the
code where we look at their "title" property. However, we
weren't monitoring that property for changes, and I'm fairly
certain Firefox at least was mapping a window and then very
quickly changing its title after. So we need to handle
dynamic changes.
Split out the wm_class mapping from the title hack. It was
messy and weird to have the two mixed because they're not
at all related, and we're not trying to handle WM_CLASS changes
right now.
Explicitly connect to notify::title in the case where we had
a title fallback. When a title changes, just treat it as
an add+remove.
In the Application Menu area in the panel, hook up to app-added
and app-removed so we get notification of the active app changing.