Updated compilation environment on Windows.

Hello Tobias, could you tell how often you or some build platform happen to build this libgmic.lib + third-party dlls pack? For every libgmic release? I have more and more people asking me more or less privately to have and test gmic-py for Windows… I am still a bit unsure about compiling gmic-py using statically prepared libgmic as yours, or pre-installing all libs before build time and using a libs lookup, copy and mangling tool for Windows python wheels such as delvewheel.