(mixal-operation-codes): Remove.
(mixal-operation-codes-alist): Immediately initialize to full value.
(mixal-add-operation-code): Remove.
(mixal-describe-operation-code): Make the arg non-optional.
Use the interactive spec instead.
Use mixal-operation-codes-alist rather than mixal-operation-codes.
(mixal-font-lock-keywords): Don't highlight comments here any more.
(mixal-font-lock-syntactic-keywords): New var.
(mixal-mode): Use it. Fix comment-start-skip.
Try to fix up minor layout issues like indentation, line break, etc...
(mixal-mode-syntax-table): Don't try to specify comment syntax,
because it doesn't work.
(mixal-operation-codes): Add some more codes.
(mixal-font-lock-keywords): Process comments here.
(mixal-mode): mixasm no longer needs -g option.
