Use the common automake module from the previous commit in the
Makefile.am's, which means that the Makefile.am's in gdk/ and gtk/ can be
cleaned up as a result.  As a side effect, the property sheet that is used
to "install" the build results and headers can now be generated in terms of
the listing of headers to copy during 'make dist', where we can acquire
most of the list of headers to "install", so that we can largely avoid the
situation where the property sheet files are not updated in time for this,
causing missing headers when this build of GTK+ is being used.

Also use the Visual Studio Project file generation for the following
projects:
gtk3-demo
gtk3-demo-application
gtk3-icon-browser
gdk-win32
gdk-broadway
gail-util

So that the maintenace of these project files can be simplified as well.

https://bugzilla.gnome.org/show_bug.cgi?id=681965