This relates to my previous commit titled "add a script to generator
files for building" on behalf of Shixin Zeng.
Tell people about the availability of a python script to create the
necessary files for a Visual C++ build from a GIT checkout.
This is done with the courtesy of Shixin Zeng's python script which does
the job and eliminates the troubles of getting a suitable shell environment
to do the "make dist" job (which is especially not easy on Windows itself!)
Don't keep the lists of source files for libglib, libgobject and
libgio in the VS project files in addition to the canonical location,
the corresponding Makefile.am files.
Instead, generate the corresponding .vcproj files at make dist time
using the C preprocessor, from template files called .vcprojin. We
still list explicitly in the .vcprojin files some of the
Windows-specific source files, and the sources files of gnulib and
pcre.