This merge request is done to improve the state of the Visual Studio build support for GSettings-Desktop-Schemas, by:
-Move the Visual Studio build files from build/win32 to win32.
-Refactor NMake Makefiles into smaller pieces, to ease maintenance, and do some cleanups.
-Fix glib-mkenums usage as it could be a PERL script or a Python script since we still support older GLib releases, by checking its type.
-Support DATADIR in the NMake Makefiles, for the possibility for using a single data directory that is not bound by the PREFIX, which is quite common on Windows.
-Support processing the translations
With blessings, thank you!