Mac OSX Provide a complete window menu implementation.

The window menu item on OSX provides a lot of functionality "out of the box".

Some of the features include:
a diamond next to the window if the window is minimised;
a bullet if the file has unsaved changes;
and
a check(tick) if the item has focus.

It would be nice to offer something based on the native menu for Qt that implements all the features of the native Window menu.