[Gtkradiant] Progress on broken Windows GtkRadiant build

[Nerius Landys]

> Hello,
> @Nerius: GtkRadiant 1.6 is working with all features usable in my Windows 7
> machine.
> What kind of enhancements are you planning to make in GtkRadiant?

Little things that may affect only Linux users.
Just one small example: If you save a map and don't call the saved
file *.map, it will save nothing and pretend as if nothing went wrong,
causing you to potentially lose hours of work.

Some issues might have been fixed in other branches so my job is to
make sure the fixes don't break anything and only improve the
situation.

In general though nothing in the way things are done such as workflow
are planned to be changed.  Strictly bug fixes IMO.