make debug channels usable in C++.
preliminary 'compute isosurface' freeprocessor.

... needs to be rewritten.  it's based on buffering up 2 slices,
running MC on that, and then replacing one slice with the next
part of the stream, then repeating.  unfortunately moving 'slice
A' to 'slice B' all the time creates craploads of memory traffic
and kills our performance over 90x compared to just a null
transport.  ouch.

so we'll need to do something more intelligent, probably by
actually having pointers to two separate arrays instead of forcing
them together.
optimizations to the MC implementation.

do the loops in the correct order.  switch to using two pointers
for the top and bottom, instead of calculating where is on its
own.  hopefully in the future this simplifies buffer management.
other small optimizations.  delete dead code.  switch to binary
i/o instead of printf nonsense... which means we can't load it in
meshlab directly, unfortunately.

these optimizations give it a 10x speedup, which makes it 'only'
10x behind what transport without isosurfaces results in.  sigh.
use a dual-buffering scheme to obviate copies.

increased performance 2.5x... we're up to 23mb/s (of 95) and MC
itself is back to being the major bottleneck.  that said, there is
still a lot of time in internal copying functions.

not sure we can do better without turning it into a true stream
processing algorithm.