Mapper 432: register 0 write also clears register 1.

Mapper 45: Only apply outer bank bits that are unaffected by the inner bank.
Mapper 45: Add PRG /CE-based menu selection.

src/boards/432.c

@@ -44,6 +44,7 @@ static DECLFR(M432Read) {
 
 static DECLFW(M432Write) {
 	EXPREGS[A & 1] = V;
+	if (~A &1 && ~V &1) EXPREGS[1] =0; /* Writing 0 to register 0 clears register 1 */
 	FixMMC3PRG(MMC3_cmd);
 	FixMMC3CHR(MMC3_cmd);
 }
@@ -51,7 +52,7 @@ static DECLFW(M432Write) {
 static void M432Reset(void) {
 	EXPREGS[0] = 0;
 	EXPREGS[1] = 0;
-	EXPREGS[2] = (EXPREGS[2] +1) & 3;
+	EXPREGS[2]++;
 	MMC3RegReset();
 }