Also allows subsequent connections, but it's broken. Don't tell the git
gods that this commit is a lie

I love git bisect! The problem was due to me accidentally deleting a
crucial condition `is_network_master` when checking for hero_switch
input.

This actually reverts the no-look-ray contrary to the apparent title

This reverts commit f41676c672.

I misunderstood the way the camera projections work, and I'm better off
using the original raycasting strategy.

Hero 1 fails, probably 0 too haven't checked though. Hero 2 is fine.
Haven't tested 3.

And Camera.project_ray_normal. This is much better

This will make testing MUCH better, I do believe.

Also, levels now inherit a level object