Change Match to take Runes and match next with wrapping.

Runes are necessary because next match needs to run the automata from each subsequent rune until it finds a match (this is what Acme, sam, and friends do). That requires the ability to read a bunch of runes, fail, go back and read more from the beginning again. RuneReader doesn't allow this since it consumes runes; you can't get them back. I was hoping to use some cool finite automata trickery to get past that. I can't. Nothing that I tried worked correctly.

Anyway, this isn't so terrible. It gets rid of the error return from match.