Fix outnum to only emit a single byte.
Add stdout lock instead of just print!'ing.
Add bfs based minimal number generation
Add more debug information
add extra debug information
converted hacky loops in png_to_piet_img into iterators and maps
add out(char) and out(num), spec finished
add duplicate, roll, and utf8 to unicode
add greater, pointer ops. add image to exec test
add subtract, mult, div, mod
cleanup move_next, add rules