Add solution and project files for Visual Studio builds

Add solution and project files for Visual Studio builds

The VS files are kept in build/win32/vs9, the same relative location
as in GLib, mostly for historical reasons.

Update README.win32 to reflect the VS possibility.

Include the VS solution and project files in the tarball when doing a
release.

To avoid having to list source files in several locations, generate
files listing source files at "make dist" time in the corresponding
source directories. Use the C preprocessor to preprocess .vcprojin
files that include said list files into the actual .vcproj project
files.

Provide a rc file for the pangocairo DLL, too.

Construct and provide in the tarball a pregenerated config.h.win32
which can be used as config.h when building with Visual C without
running any configure script. Provide pregenerarated
module-defs.h.win32, module-defs-lang.c.win32 files too.

Define PANGO_MODULE_PREFIX appropriately in the relevant module source
files if not available from the compilation command line.

Update module-defs-fc.c.win32 and module-defs-win32.c.win32 to match
what the configure script provides.