Remove a lot of warnings (considered as errors by dune).

nb : i have changed the var name in the generated nodes, which was a bad idea
(=painful to get it rigth again).

The bug was appearing a node was called on a non base clock that was
existing in the called nodes (name clash). Typically, it occurs on
recursive node called on some non-trivial clocks.

Also, use maps instead of list to hold the substitution between
params and args.

More precisely, I missed clock in the ve_clk field of val_exp.

and replace enumerated clock in the var_info even if it does not
appear in a val_exp.

nb : luciole-rif is now  in the rdbg repo.

var_info appears in
- node decl
- left var
- static args

not yet working. I commit as Ive fix a missing dep on WenOnId in the _oasis.

More precisely, transforms equations of the form

   y = x when Toto(c);

into

   x when Toto_c ;
   Toto_c=Toto(c);

Ditto for Misc and Compile

Indeed, having two different mechanisms is bad.

In the end, I've kept mine (and not the one of Pascal), because the
it was depending on LicPrg.t, which was creating a circular dep
(which could of course be fixed, but I am lazy).

  More precisely, a node that has memory ougth to be declared using
  "node", and using "function" otherwise.

  Moreover, a node that performs side-effects (i.e., if it calls an
  extern node that performs side effects) ougth to be declared as
  "unsafe".

  Safe/unsafe mismatches raise an error.

  Memory mismatches raise an error in one way (a "function" that uses
  memory), and a warning in the other way (a "node" that uses no
  memory).

Also fix some errors done when transmitting the unsafe flag (well, it's
the first time I use it!).

- predef Lustre op were declared as memoryful.
- expr like "if true then ..." were badly translated
- The clock and types of some expressions created by L2lOptimIte had
  a bad arity (in presence of tuples)
- in order to perform the -oite optim, also check that each branch is safe.

Indeed it is possible when each branch of the ite updates no memory.
This is done in the new L2lOptimIte module.

For the time being, it does detect when the node has no memory. It
only looks at the declaration: nodes have memory, and not functions.

I should infer that information and raise warnings or errors if what
I infer is not compatible with waht is declared (will come later).

Also split ActionsDep into ActionsDep and Action.

Also fix a bug in L2lsplit where deeply nested (>2) merge were not
splitted.