de-exported the nfa_to_pfa functions and friends, not sure they need exposing

things worth notign are the repl command "dump_dict" which writes the dictionary to /tmp/dict
traceON and traceOFF which will log the words executed on the console, there's a vtable mechanism for adding in-band signalling words that will usurp any dictionary words. They were introduced for debugging. I shall leave them there for now.