The generation scheme is now makes it easier to write oracles that do
not depend on the topology.  The idea is to generate an oracle
(specific to the graph) that includes a file that the user should
provide, and which ougth to define a generic oracle, i.e., depending
on m and n (process and actions numbers).

merge origin/3-compute-the-graph-degree-diameter-etc

nb: this demon is not fair: it is biased by the degree of nodes.

the doc generation should not be run on a docker that does not have emacs

Add the doc generation in the test to avoid such CI failueres in the future

Add use it to add an oracle to the BFS

Took into account Erwan's comments and changed Register module such that the properties are computed on first call (except height that is computed on each call because it depends on the chosen tree's root)

Add use it to add an oracle to the BFS

Fix: take into account in dot.ml the change in Topology done in #e76aa9be

where a weigth label has been added

Basically, the idea is to parse the result of the registred ('s ->
string) function.

For instance if  the user define 'v and 'v printer as follows:

 type state = { a : int ; b : float }
 let state_to_string s = Printf.sprintf "x=%d y=%f" s.v1 s.v2

pid_x and pid_y will be used as output var names in the RIF outputs.

If the user provide no name:
 let state_to_string s = Printf.sprintf "%d %f" s.v1 s.v2

some names will be invented (pid_v0 and pid_v1)

All the get_* functions (that are of no interest for users) are now in
the Register module.

Things that are currently broken:
- the ability to init vars in the dot
- controling the name of local vars in the rif output

The idea is to use the Obj module (arg !!!), which is safe thanks to
the fact that there is now only one register function, which forces all the
'v to be bound to the same type.

But I bumped into the "value restriction" limitation
https://stackoverflow.com/questions/22507448/the-value-restriction

Indeed, I need to store functions of 'v in some tables (or references),

And tables are necessaryly weakly polymorphic !

https://v1.realworldocaml.org/v1/en/html/imperative-programming-1.html#side-effects-and-weak-polymorphism

Indeed, by using the Env.nset and Env.nget defined in
0d6575a7 a pb that was hided by the
use of Env.set and Env.get was triggered.

The bug was that variables initialisations were done several times.

In sasa.ml, the way I was updating the Env.t by iterating on the
variables was forcing to "close" expressions that were calling init
functions.

More precisely, they were not consistent by the behavior of -custd mode.
Indeed, It was returning the values of variables after the step is performed.

In the custom demon mode, sasa returns Enab and variable values before
the Activate is computed by the demon.

Chosing one behavior or the other is arguable ; the main advantage of
this choice is that we don't miss the initial values.