VirtualGL setup

There is no apt-friendly way to do this without considerable effort.

Some modules might need to be manually unloaded for this to run without errors.

I answered yes to 'Restrict 3D X server access to vglusers group?'; No to 'Restrict framebuffer device access to vglusers group?'

This requires users of this feature to have an

sudo adduser *username* vglusers