Linux build for V4

As the title suggests, the Linux version is now out. It seems to run fairly slowly on my laptop (low FPS), but my Linux machine is very old, at this point, so hopefully will run fine on a normal computer.

Otherwise, work can now begin on the next version. Hopefully introducing a new name of evil to play as, themed around politics and fear. Maybe also introduced an organised defence against the darkness (with an option to disable, for a more relaxed game). We'll have to see how development goes.

Hope you're all safe and well.