macOS build

Managed to get hold of a mac machine to see if I could get the 1.0 release of GOT3D released on macOS. With some small changes and a bit of testing it looks like everything is good to go for a macOS release.

A few notes on this release. It isn't signed, so you will have to confirm installation/opening within the privacy setting on macOS. This will not be released on the App Store so any official code signing will not happen. 

This was tested on an M2 machine running macOS 12 with 8GB RAM and was super scaled over the default resolution and ran at 60fps without issue (using a PS5 controller). I assume this will be able to run on more modest hardware but I couldn't give a 100% guarantee of the minimum spec you need, so your mileage may vary.

I will try and get this build added to the Steam release if it makes sense.