Space Raiders (Psion/ Mikro-Gen) - Patch to use cursor keys in addition to the standard keys

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Original Code:

$4538: LD   A,$FE
       IN   A,($FE)
       BIT  1,A
       JP   Z,$4520
       BIT  0,A
       JP   Z,$4559
       JP   $457A
$4549:

$45A3: JP   NZ,$45C7
$45A6:

$407B: DEFB $5C
$407C: DEFB $6A

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Changes are as follows:

$403C: 28 0B     JR   Z,$4049

       3E FE     LD   A,$FE
       DB FE     IN   A,($FE)
       CB 4F     BIT  1,A         ; Check for key 'SHIFT'.
       CA 20 45  JP   Z,$4520

       CB 47     BIT  0,A         ; Check for key 'Z'.
$4049: CA 59 45  JP   Z,$4559

$404C: C3 7A 45  JP   $45A6

$404F: 28 09     JR   Z,$405A

       3E EF     LD   A,$EF
       DB FE     IN   A,($FE)
       CB 47     BIT  0,A         ; Check for key '0'.
       C2 C7 45  JP   NZ,$45C7

$405A: C3 A6 45  JP   $45A6
$405D:

$407B:           DEFB $E2         ; Patch the LOAD CHECK checksum bytes, which
$407C:           DEFB $AE         ; have changed values due to the modifications below.

$4538: 3E EF     LD   A,$EF
       DB FE     IN   A,($FE)
       CB 57     BIT  2,A         ; Check for key '5'.
       28 E0     JR   Z,$4520

       3E F7     LD   A,$F7
       DB FE     IN   A,($FE)
       CB 67     BIT  4,A         ; Check for key '8'.
       C3 3C 40  JP   $403C       ; Continue the check for the direction buttons in the printer buffer.
$4549:

$45A3 C3 4F 40   JP   $404F       ; Continue the check for the fire button in the printer buffer.

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