bugfixes hf mf sim

- output of debug messages caused communication failures due to timing issues.
  hf mf dbg 4 now required to see these debug messages.
- changed help text for hf mf dbg
- fixed minor bugs in help texts for hf mf sim and hf mf ecset
- display "key A" or "key B" instead of "key=0" or "key=1 in hf mf sim