Change to agent application, with visible menubar item.

Hi Dan,

I finally got round to looking working on this!

This change,
- Adds "Filament" to the menu bar,
- Removes the the main application window.
- Changes the app to become an "agent" - meaning it does not appear in the dock or task switcher.

On the latter point, if you go to Finder (or any app with few menus), you'll see Filament's menu in the menu bar.

=)