Stopped the C128 mouse drivers from blocking certain keys such as '1', '2', and 'Q'.

This extra fix is needed because the C128 keyboard scanner works a little differently than the C64 scanner works.
Fixes #696. Fixes #853.

libsrc/c128/mou/c128-1351.s

@@ -4,7 +4,7 @@
 ;
 ; 2009-09-26, Ullrich von Bassewitz
 ; 2014-04-26, Christian Groessler
-; 2014-04-30, Greg King
+; 2020-07-14, Greg King
 ;
 
         .include        "zeropage.inc"
@@ -377,7 +377,7 @@ IOCTL:  lda     #<MOUSE_ERR_INV_IOCTL     ; We don't support ioctls, for now
 IRQ:    jsr     CPREP
         lda     KEY_COUNT
         sta     old_key_count
-        lda     #$7F
+        lda     #$FF
         sta     CIA1_PRA
         lda     CIA1_PRB                ; Read joystick #0
         and     #$1F

libsrc/c128/mou/c128-inkwell.s

@@ -2,7 +2,7 @@
 ; Driver for the Inkwell Systems 170-C and 184-C lightpens.
 ;
 ; 2014-04-26, Christian Groessler
-; 2014-09-10, Greg King
+; 2020-07-14, Greg King
 ;
 
         .include        "zeropage.inc"
@@ -414,8 +414,8 @@ IRQ:    jsr     CPREP
         ldy     #%00000000              ; Set ports A and B to input
         sty     CIA1_DDRB
         sty     CIA1_DDRA               ; Keyboard won't look like buttons
-        ;lda     #%01111111             ; (Keyboard scan leaves this in port A)
+        lda     #%11111111
-        ;sta     CIA1_PRA
+        sta     CIA1_PRA
         lda     CIA1_PRB                ; Read Control Port 1
         dec     CIA1_DDRA               ; Set port A back to output
         eor     #%11111111              ; Bit goes up when button goes down

libsrc/c128/mou/c128-joy.s

@@ -3,7 +3,7 @@
 ;
 ; 2009-09-26, Ullrich von Bassewitz
 ; 2014-04-26, Christian Groessler
-; 2014-05-01, Greg King
+; 2020-07-14, Greg King
 ;
 
         .include        "zeropage.inc"
@@ -379,7 +379,7 @@ IOCTL:  lda     #<MOUSE_ERR_INV_IOCTL     ; We don't support ioctls for now
 IRQ:    jsr     CPREP
         lda     KEY_COUNT
         sta     old_key_count
-        lda     #$7F
+        lda     #$FF
         sta     CIA1_PRA
         lda     CIA1_PRB                ; Read joystick #0
         and     #$1F

libsrc/c128/mou/c128-pot.s

@@ -4,7 +4,7 @@
 ; 2006-08-20, Stefan Haubenthal
 ; 2009-09-26, Ullrich von Bassewitz
 ; 2014-04-26, Christian Groessler
-; 2014-05-05, Greg King
+; 2020-07-14, Greg King
 ;
 
         .include        "zeropage.inc"
@@ -385,7 +385,7 @@ IOCTL:  lda     #<MOUSE_ERR_INV_IOCTL     ; We don't support ioctls for now
 IRQ:    jsr     CPREP
         lda     KEY_COUNT
         sta     old_key_count
-        lda     #$7F
+        lda     #$FF
         sta     CIA1_PRA
         lda     CIA1_PRB                ; Read port #1
         eor     #%11111111              ; Make all bits active high

libsrc/c128/mou/callback.inc

@@ -1,11 +1,12 @@
 ;
-; Callback routine called from the IRQ handler after the ROM IRQ handler
+; Callback routine, called from the IRQ handler after the ROM IRQ handler
-; had been run.
+; has been run.
 ;
-; Christian Groessler, 24.04.2014
+; 2014-04-24, Christian Groessler
+; 2020-07-14, Greg King
 ;
 ; Check if there was button/joystick activity before and/or after the ROM handler.
-; If there was activity, discard the key presses since they are most
+; If there was activity, discard the key presses because they are most
 ; probably "phantom" key presses.
 
 callback:
@@ -16,7 +17,7 @@ callback:
         lda     OLD_BUTTONS             ; keypress before?
         bne     @discard_key            ; yes, discard key
 
-        lda     #$7F
+        lda     #$FF
         sta     CIA1_PRA
         lda     CIA1_PRB                ; Read joystick #0
         and     #$1F