Added Matcher.regexp(). Woo.

Also clarified docs on Line.matches(). It's not like j.u.r.Matcher.matches(),
but rather j.u.r.Matcher.lookingcAt().
Fix beans/frank in Buffer.findBackward.
Fix bounds error in CSMatcher.search().
More indenter improvements.
Useful error message for assert.
Revamped align indenters.

Made it easier to use Matcher.regexp for anchor &c, switched most matchers to
regexp to ensure proper word boundaries.