Changelog
---------

2012-08-03: Mild rewrite to adapt the mod to use perlin noise while spawning. 
Also got rid of the random-numbers-inside-abm stuff, now using the abm's own 
'chance' parameter instead.  Tuned various settings to try to retain the same 
overall density and growth rates as in the previous version.  Moved this 
changelog into a separate file.

2012-07-12: moved project to github.

2012-07-09 (a bit later): tuned the spawn/grow rates a bit more, made the 
numbers more sane.  Added a radius check to limit the density of the spawned 
grasses (they won't grow near each other or near dry shrubs or cactus, though 
they still grow on the top of said cacti).

2012-07-09: Added cactus, sand, and desert sand as spawning surfaces.  Reduced 
and tuned the spawn rates a bit to try to balance things out.  Made that which 
spawns on grass, dirt, or sand start out at any size, grow over time, and 
eventually die off.  Limited desert sand to only the first two sizes (the 
smallest size will grow one step, eventually), which will eventually die and 
turn into dry shrubs.  Only the two smallest sizes can spawn on cactus or 
papyrus (and they don't grow or die).  Fixed slightly off-center smallest size.  
Fixed selection boxes.