wineshelllink: Use FreeDesktop standard to create Wine menu structure.

[Dan Kegel]

Vitaly wrote:
> [xdg-utils] can not handle files with spaces in them.

If that's true, it's a bug, and should be fixed.

> Also they don't allow installing icons without specifying size.

? http://portland.freedesktop.org/xdg-utils-1.0/xdg-desktop-icon.html
doesn't seem to talk about sizes at all.

> [We can't just check the scripts into the wine source tree
>  and require their installation.]

Why not?  If they save effort and work well, let's do it.
- Dan