NT build environment/versioning

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

I reworked the versioning system to have a central
place to make changes necessary for release.   Currently
its 'version.sh', a bourne shell script.  Obviously
this won't work under MSVC.

Likely the version information should be moved to
a simple file with key/value pairs (maybe 'version')
which can then be used by each build system.

As I'm not familiar with MSVC, I am not sure of the
best approach to integrate such a system.  A volunteer
is needed to work out a reasonable solution for both
configure and MSVC versioning.  The key requirement
is that all version information must be derived from
information contained in a single file.

Kurt