Late christmas present. Due to the way alpha works on the model3 adding regular anti-aliasing doesn't really work. Supersampling is very much a brute force solution, render the scene at a higher resolution and mipmap it.
It's enabled via command line with the -ss option, for example -ss=4 for 4x supersampling or by adding Supersampling = 4 in the config file.
Note non power of two values work as well, so 3 gives a very good balance between speed and quality. 8 will make your GPU bleed, since it is essentially rendering 64 pixels for every visible pixel on the screen.
