segfault somewhere
new design, stack tests work
dict read write and add
bytes read and write
dict lookup
add string, match on length only
string lookup on length and contents
a bit of refactoring
some number tests, still only positive, though
parse and push negative numbers
evaluate and push numbers
run an unknown word
tinkering with word lookup and execute
fixed a test problem, now finds and calls a fresh word
changed string functions to be single-ended (0 terminates)
refactored to single-ended strings, added word def test
a bunch of cleanup preparing to bring this branch back onto master