Windows improvements

There are some improvements that we can make on Windows.

Look correct on Windows XP and later

See issue 312 and DUIM.

Include PellesC into the releases

If we bundle PellesC with our releases, we could get away with a much improved first time experience on Windows.

See Windows Installer.

Be able to build everything with PellesC

I'm not sure how much work this is to build without nmake and friends. The idea is that someone should be able to do a fresh build of the IDE with PellesC.

This would probably require adjusting a couple of things with MPS as well so that we're really doing the full build with PellesC and no more VisualC 6.