Version 0.5

Update blinking when window is closed.
Replaced WinIconManager class with function manage_winicons().
Added ManagedTray for trays managed by an IconManager.
Removed Config.*_attribute() methods.
Expose WinIconManager.screen.
Moved get_custom_menu_items() from Tray to MenuIcon.
Passing additional arguments to menu icon constructor.
Pass wnck screen around.
Add $APP_DIR/icons to icon theme path (in Main.mainloop()).
Removed Attribute.set_func.