automatonset

We should create an automatonset, or actually, several automatonset: they should be parameterized with the same tags that already qualify some constructions such as sum: standard_tag, deterministic_tag, etc.

Start with a simple one, e.g., standard_tag, and then, enlarge it to cope with more case.

An interesting question is whether the automatonset<standard_tag> should be implemented using sum<standard_tag>, or the converse. This should be evaluated.