galsdk 0.9.0

This is the first packaged release of galsdk. I've arbitrarily started the version number at 0.9.0 to reflect that the tools have been in development for a while but still aren't at a point that I would call 1.0.

Currently only Windows releases are provided. If I ever get the editor working on Mac, I'll provide releases for that platform as well. I'll probably also provide a Linux AppImage at some point because why not.