doc stuff
---------
add more info about using the modules and sample nets.

code stuff
----------
finish real ocean model
finish Water module

add Noise/Turbulence module? check perlin.c for bugs

should do Group stuff in all modules

conversion of DXField size to MyField size is ambigous
(i.e. width/height/delta stuff, assume equal deltas in x/y directions)
irregular grids won't work...

should turn integer args into real position args
(e.g. coords instead of array indicies)

should default height in raise fns to be correct

future stuff
-------------
lightning
fire

characterize parameters for different surfaces (e.g. mountains, plains, etc.)
sandbox effect on erode fns
add more parameters to erode stuff

make a "debug" stream class: e.g.
---------------------------------
coutd << "debug message" << ... << endl;
coutd << debug_level(4) << "debug message" << ... << endl;
coutd << debug(MemDebug) << "debug message" << ... << endl;