Like the install projects that were fixed few days ago, the gengir projects
did not have info on the intermediate and output directories as a result of
the split up of the property sheets. Fix this by including the appropriate
property sheet in the gtk-gengir property sheet so that we can avoid
confusing messages from Visual Studio on whether to reload the gengir
project as it was modified, at least on 2008.
-Add Visual Studio 2008 projects and pre-configured gdkconfig.h for
Broadway builds
-Decouple the Visual Studio property sheets, to simplify maintenance and
enhance flexibility for different builds
Visual Studio 2010 projects updates will follow later.