Rhino 6 builds

@pascal, I just installed R6 on a new pc and noticed it loaded three different C++ redistributables. Time for some refactoring maybe…

Yes, it’s true. That’s because of some third-party libraries that we ship with Rhino that use the older C++ redistributables. At this point, our only reasonable options are to drop support for some file formats that use older libraries, or install all three. We chose the latter.