* refactor: simplify & unify find_method in both Tracer and Debugger, st a diff now shows in what they still differ essentially
* factored out find_method to superclass InterceptedGrammarHOW, which now manages the common part of the state: indent, aka call-depth wrt regexes (ie. without any wrappers or calls to a grammar's non-regex methods from within a regex)
* the pattern is now also a bit more safe in that we first call back private "onFoo"-methods which in turn call the subclass's methods. That way we ensure that *our* part of the state is properly updated/kept and not fiddled around with
* get better diagnostics if test fails due to exception
* InterceptedGrammarHOW: make private callbacks onRegexEnter/Exit more generic by expecting a Method / a Method and a Mu (result), resp.
* switched order of params $match and $indent in &summary, so it's the same as with (subclass's) &onRegexExit
* add comments where (maybe) needed and remove 'em where (now) not
* move ANSIColor related stuff back into Tracer, *have Debugger inherit from it*