s/data/fdata/ for sdcc 3.1.0
hxstream: add pointer annotations
initialize local statistics (they're in xdata)
compiler: enforce --nooverlay flag

*  I still don't completely understand what overlay means in this
   compiler, but Tridfe recommended this change
hxstream: buffer indicies are now in data (close ram), uint8_ts
export and debug buffer indicies

* there may be a bug in the buffering code, based on some crashes I've
  observed, but I havent found anything conclusive yet