"fix" deadfish overflow using ΙΧΘΥΣ to allow x=256 (and x>256)

[hornc]

This is a more difficult version of #7 , it should allow the printing of Ā (using composed characters?) and the appearance that x (the accumulator) can have the value 256, and that the deadfish overflow is only occurring on x == -1

Should be possible, but quite complex, most builtins will need to be overwritten. Might not be possible?