Removing some of the old VC++ stuff

Hi!

I would like to suggest that we retire some of the old Visual C++ build
infrastructure. Specifically, all the makefiles for VC++ 6.0 *except* libpq.

There is a point for keeping libpq - if you want to build a static
version, it's easier if you can use the same version. And it's also
required if you want to be able to use the PQtrace function. Therefor, I
suggest that we keep both the VC++ and Borland makefiles for libpq
(since we do seem to have someone touching the Borland stuff every now
and then we can keep it, but I wouldn't consider it "properly
maintained" :-P)

The argument for removing the rest of the support is that it will get us
away from having to maintain it :-) The build files can be generated
automatically for Visual C++ 2005 using the new code (and you can build
just the frontend part sif you want to), which is available as a free
download from MS.

Anybody think we need to keep those around?

//Magnus