Add/remove for DAFSAs

[larsmans]

Just to let you know, there's a variant of Daciuk et al.'s algorithm that supports adding a string to an DFA, retaining minimality:

• Incremental Construction and Maintenance of Minimal Finite-State Automata

(I've been toying with these things myself lately, but didn't come round to publishing any code.)

[danieldk]

Thanks! I think I have seen that paper before. I might add a mutable variant at some point, but the representation in the final automaton (which uses several arrays of primitives, since Java doesn't allow you to use unboxed classes) may not be that great/efficient for mutation.

My first goals is to have some work-alike for Guava's immutable collections where the key (or key and value) is a String.

Of course, patches are welcome :).