'readmail' perverts the final terminator

[ttw]

Seems like 'readfile' converts the last character of the line to a "\n" when it finds it missing for it's read; kinda ironic that I noticed this during corecode/dma#18 since it actually allows an extra byte into the input (should be 998 and the ommission of the CR allows 999). Anyway, it's all semantics really, don't think it's functionally interesting.