Fixed the following bugs:
- the buffer was reprinted endlessly when msg.bufx == 0 and (for a
different reason) when msg.bufx == 1.
- the last byte of the buffer wasn't printed except in the the infinite
loop cases.
- the comment about walking the buffer didn't match the (correct) code.
- minor -Wall and style bugs.
Not fixed:
- excessive newline processing which hid the non-printing of the last
byte of the buffer.
