hxstream: when forced to drop a frame, reset the parser state to idle
hx framing: track errors internally
more debug variables
track biggest tdm window (for sanity check)
panic msg should now go out via hx term
golay: check loop invariant & panic
tdm loop watchdog: reboot when timer2 detects main loop is hung
hxstream: change storage class of insert, state
hxstream: lots of storage class annotations have reduced crashing

* ran twice for over 10 mins without hanging, thats pretty good
* has (new?) issue where tdm eventaully loses sync and never
  regains - took 15 < t < 45 mins in single time i saw it
reinstate activity light (was disabled for debugging)
move statistics and errors to xdata

* just cargo culting, honestly
at processing: sprinkle volatile, move buffer to xdata

* guard in at_input_aux might do something???
* totally cargo cult
tdm: issue ATI0 command at start of loop.
init errors struct (since xdata boots up as noise)