Changes

* Guaranteed linear-time searching (with relation to the corpus size), because it makes automatons rather than doing backtracking—nice size—nice for fending off DOSesDOSes—is probably not a unique advantage anymore. [Actually, I'm not sure PG and ES or PG don't do that as well. The seem to use DFAs rather than backtracking for regex execution these days; the Lucene RegexpQuery is a subclass of AutomaticQueryAutomatonQuery.]