Adapt the Visual Studio project files to output the introspection files
in the same directories where the built binaries are located from the
previous patch.
Also, make the gtk3-introspect project dependent on the gdk-3 and gtk-3
projects only, so that we can build the introspection files without
needing to finish the whole build process. In order to "install" the
built introspection files, the gtk3-install project is now where this is
being done. Note that the introspection builds is still not built by
default at this point.
This is so that it is easier for one building GTK+ with Visual Studio to
build the introspection files as well in one shot. Note that this is
not built by default, so one needs to select the gtk3-introspect
explicitly to build (and clean up) the introspection files.
For this to work, one needs to ensure the following:
-A complete build of GObject-Introspection in $(GlibEtcInstallRoot),
that is built with the same installation of the Python interpretor that
is used here (see PythonDir and PythonDirX64 in
gtk3-version-paths.[vsprops|props]).
-Introspection files for ATK, GDK-Pixbuf and Pango, also in their proper
locations under $(GlibEtcInstallRoot), which should be built with the
same G-I installation.
