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

This can be used from rdbg from example, to generate session files.

In particular, 'rdbg -lurette' now works thanls to this option
(cf rdbg sha 63566a893807361691137cafe15854a2a7395eec)

Remove the --generate-rdbg-load one that is less general

Actually, I've just realized that the I/O mode of rdbg already makes
it possible to use sasa from rdbg (exit event only). This plugin would
only be necessary when we would need a finer grained intrumentation, e.g.,
to stop at enable step, or to at each process call/exit.

This is necessary to be able to use sasa with luciole.  Indeed, in
rdbg/lurette, luciole always plays first. Hence if we want sasa to
play after luciole, we can use the option.

Note that from the lurette point of view, sasa plays the role of the env
as it needs to start playing, to provide Lutin the enable values for
the first demon step.

with algo several actions, and allow lurette to chose them.

Also add the list of neighbors to the init function. The rationale is that
to give a sensible initial value to local vars of type 'Neighbor', we need
the neighbors number.

I could have chosen to pass an integer only. Well, who can the plus
can the minus.