regex improvements for filter
regex improvements for filter

For example, actually compiling the regex, using the Java regex engine
etc. Still think this is pretty slow compared to n-gram comparisons.

tdomhan/thrax,joshua-decoder/thrax,joshua-decoder/thrax,jweese/thrax,joshua-decoder/thrax,joshua-decoder/thrax,jweese/thrax,jweese/thrax,tdomhan/thrax,tdomhan/thrax