* Fix radio error-message parsing bug: old comparison against error
prefix string off by the size of the Starmode link-level protocol field.
* Fix radio reset finite state machine, given that parsing works properly.
* Add debugging messages about reset FSM if IFF_DEBUG is set.
* Remove #ifdefs notdef around back the check that discards newlines at
the beginning of a frame. Every error message from the radio has a newline,
as the radio send error messages terminated by \r\n, not just \r like data
frames. Not dropping the \n garbles the following data frame.
* Remove unused low-level debugging routines.
* Reformat the low-level bytestuff/RLL code to match the canonical source.
* Reduce MTU to 1100 bytes; 1200 bytes can overflow the radio buffers if the
bytestuff/RLL does poorly.
* Fix radio-probe string to _not_ include a frame delimiter (\r): sending
a \r to the radio tickles a bug in the firmware, causing the radio to
smash the next frame sent after the "**\r" probe string.
* Add calls to the tty t_oproc routine to make sure the probe and reset
strings get sent to the modem promptly, rather than waiting for the next
packet.
* Add PPP-style calls to the tty start-output function; seems to
reduce latency marginally.
still to do:
* Flush output queue if resetting, since the radio is going to drop
frames on the floor anyway if it needs resetting.
* Reduce tty start-output calls.
