Support for 64bit and VapourSynth

This is a minor update which offers support for windows 64bit Avisynth players, as well as VapourSynth.

For convenience, the binaries are now offered on Github, along with the source.

To build from source, one needs from now on to build the plugin from the Visual Studio GUI, since microsoft has stopped supporting command line builds using nmake. Thereby also putting an end to any notion of being able to offer automated and verifiable builds using a CI pipeline.