Clean up Visual Studio Build Files

-Combine entries in the property sheets and make it a bit more flexible,
 and drop some redundant items
-Use Custom Build Rules for generating enumeration and marshalling sources,
 and the .def file so that they can be wiped off when a "clean" is
 requested, and regenerate automatically when the templates/.symbols
 files are updated.
-Improve consistency by using ApiVersion rather than ClutterApiVersion
 with the Visual Studio project for other components of the Clutter/GTK+
 stack
-Get rid of unneeded configs in the "install" project