Fix Signal enumeration

- Signal.X.ordinal() == Signal.X.signal()-Signal.NUL.signal()
  - X<NONE
- preset kernel matrix transitions to signal NUL everywhere all the time

Signed-off-by: jrte <jrte.project@gmail.com>

src/com/characterforming/jrte/engine/Model.java

@@ -512,10 +512,10 @@ protected long[] readTransitionMatrix() throws ModelException {
 			matrix = new long[nStates * nInputs];
 			// preset all cells to signal NUL without changing state
 			for (int state = 0; state < nStates; state++) {
-				final int toState = state * nInputs;
-				final long nul = Transducer.transition(toState, 0);
+				final int base = state * nInputs, toState = base;
+				final long nul = Transducer.transition(toState, Signal.NUL.ordinal());
 				for (int input = 0; input < nInputs; input++) {
-					matrix[toState + input] = nul;
+					matrix[base + input] = nul;
 				}
 			}
 			// fill in defined transitions

src/com/characterforming/ribose/base/Signal.java

@@ -54,16 +54,16 @@
  *
  */
 public enum Signal {
-	/** Signals nothing, for optionality (use as null) */
-	NONE(new byte[] {}, -1),
 	/** Signals first chance to handle missing transition on current input symbol */
 	NUL(new byte[] { 'n', 'u', 'l' }, 256), 
 	/** Signals anything, used as a generic out-of-band prompt to trigger actions */
 	NIL(new byte[] { 'n', 'i', 'l' }, 257), 
 	/** Signals end of feature, used as a generic feature delimiter */
 	EOL(new byte[] { 'e', 'o', 'l' }, 258),
 	/** Signals end of transduction input */
-	EOS(new byte[] { 'e', 'o', 's' }, 259);
+	EOS(new byte[] { 'e', 'o', 's' }, 259),
+	/** Signals nothing, for optionality (use as null) */
+	NONE(new byte[] {}, -1);
 
 	private final Bytes sym;
 	private final Bytes ref;