Add neigh type (struct composed of state, reply and weight), add 3 new function for neigh type, add state.lus generation by salut, modificate unison,bfs-spanning-tree and rsp-tree (compare and kind2 work\!), add demon_is_valid function, a new constant (liste of neighbors number), modificate algo for the new to_state function

and add the untracked ring.dot files that broke them

(disconnect component detection)

Its basename is the basename of the name of the .dot file.

Also provide a =--gen-register= option generates such a registring ml
file. --gen-register also generate a state.ml skeleton file.

The Makefile test/Makefile.inc also suppose that the types of the state
is defined in state.ml

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.