Just partially connected to existing theory

    terms can be grouped and scheduling of those decisions freezed

      Egraph.Ro.t is Egraph.rt and  Egraph.t is Egraph.wt

Use more first class function for attaching event. The second part scheduled
keep the Dem.t type.

 Modifications made by François Bobot, Stéphane Graham-Lengrand and Guillaume
 Bury. The witan licence has been used for the files not mainly modified by Bobot

  - types need to be renamed in popop_types thanks to ocaml module of
    the same name

  For theory initialization

[Ty] Ty moved to Types. It is not a domain anymore, it is a static property of a class
[Bool] add a specialisation for the equality
[Arith] add the real type everywhere

[Solver|Arith] Work but with many hacks problems with the daemon are registered not delayed but the effect are. They look at only one place

[Test] add some of altergo tests