Windows and Mac builds added

Added Win64 and OS X builds, as the HTML5 build (using WASM) apparently has issues on some browsers.

Note that the OS X build is untested, as I only have Windows, Linux, and Android systems/devices currently.

Also, this is still the original jam edition, so basically just platformer mechanics - no actual level design or gameplay or anything. I had a pretty good time getting started with Godot, though, so I'll definitely work a bit more on this later, implementing the ideas I originally had for the game.