public final class ByteMatrix
A class which wraps a 2D array of bytes. The default usage is signed. If you want to use it as a
unsigned container, it's up to you to do byteValue & 0xff at each location.
JAVAPORT: The original code was a 2D array of ints, but since it only ever gets assigned
-1, 0, and 1, I'm going to use less memory and go with bytes.