Stop trying to create a 'gasp' table

Stop trying to create a 'gasp' table

As far as I can tell, the "GaspTable" line that I put in the SFD file
has never actually worked.  I don't think I want it to anyway: even
when the source pixels line up precisely with the display pixels, it's
still worth having anti-aliasing on the diagonal lines.  And of course
none of this would work properly for any width other than the default
one.

So overall, it doesn't work, and if it did I'd want it to stop.  So
let's remove it.