One more thing: Also changes the printString of ASCII-13 to #return because it seems more readable than #cr.
Note that I pushed readability more into the direction of recognizing physical keys, not standard ASCII labels. I hope that's fine... In that sense, the printString for #lf might be also changed to #linefeed, which is already there.
But is there a keyboard with a line-feed key? I know that the "Enter" key on the num pad does not arrive as ASCII-3 (ETX, end-of-text) on all systems, right?