cleanup
Allow synonyms longer than the answer can be (since we may take substrings)
Make sure len(parents) == len(c.Args)

Previously, clue.HashString() would totally skip non-printing sub-clues
(like DEF, NULL, ANA_, etc.). This caused the parents list and the args
list to fail to line up.
Don't take word substrings which are just the entire input word
more careful checking of indicator type
Add serial mode for debugging
update indicators and known clues