tighten up MSB loop, almost works
remove MSB decode warning, as we aggressively test

also sprinly various print debugs for MSB, there is a timing issue related to the 2nd byte of a '\x1b[A' sequence failing the kbhit() check. I think i've seen this before, has to do with flushing something correctly at a particular time? will look tomorrow.
add this temporary test script