The code here is significantly cleaner if we use the data Metacity
already has cached and validated, rather than talking to X directly.
Also some preparatory work for extending the monitor API by
clarifying the name of the (current) main entry point.
ShellAppMonitor now depends on gmenu to load menus.
Use the menu data from ShellAppMonitor to show a menu list.
GenericDisplay implementations can now have a sidebar area. We
handle keystrokes such as left/right explicitly.
Some internal API changes to account for the fact that a display
can have another filter in addition to the search.
