Improve the automaton generator

[Drup]

This is sort of a todo note, as I don't really have time to work on it right now.

It would be very interesting to compare this with the current approach and potentially implement it. A interpretor approach have been implemented https://github.com/pippijn/dreml. Some solutions for Unicode have been introduced here.

Would solve https://github.com/alainfrisch/sedlex/issues/5 https://github.com/alainfrisch/sedlex/issues/20, among other things.