Add an interface to allow for items to be added to the application "window menu".

[tstanley]

It would be convienent at times to be able to insert items that would appear alongside the default Restore/Move/Size/Minimize/Maximize/Close items in the "window menu" that pops up when the icon in the top left of the application is clicked (or the alt-space key), such as seen with Windows' own Command Prompt program (see screenshot).  Thanks.