[ab] Back to the 90's: Metaballs

[Luke Crook]

I have added a 'Metaballs' example in lispbuilder-sdl-examples. The fastest 
that I get this example to run is about 13 fps in CLISP and around 45fps in 
Lispworks on an AMD 2200. This is pretty slow as far as I am concerned. It 
seems that Lispworks runs at about the same speed as the equivalent version in 
Java ( http://processing.v3ga.net/show.php?id=10&type=0 ).

So if anyone has the time please take a look at 'metaballs.lisp' in lispbuilder-
sdl-examples and provide some feedback as to how this example might be sped up.

Thanks,
- Luke