Outputting sprites to 256 greyscales gave an unknown or missing variable
due to ms$ instead of m$ in an IF statement.
A comment added to table lookup mode contained colons inside assembler
brackets.
Finally figured out why the bottom corner of the screen sometimes gets
messed up,there was a SWIEQ 256+ASC"A" festering in the B&W lookup table
code (been in for years!).

Version 1.21. Tagged as 'ChangeFSI-1_21'