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

(which breaks lurettetop)

nb : Mamadou's change broke some tests (18->53). Empty body is
generated for nodes that have one eq.  I'll fix that later.

by grouping instances of the same type into arrays.

The rationale is to be able to generate for loops with iterators.

The previous code was working, but probably by chance.

Indeed, in order to sort Soc.gao, I currently process in 3 stages ;
1. compute a total ordering of Actions.t according to the deps
2. transform Actions.t into Soc.gao (List.map)
3. factorize Soc.gao by looking at consecutive gao that have the same guard

With this change, between steps 1 and 2, I reorder the list of actions
so that group of independent actions are sorted according to their
clock. The idea is of course to provide to step 3 more opportunities
of factorization.

The result is not very convincing yet.

I've also tried to sort the actions wrt their clock before performing
the toposort. Seems not too bad.

I've kept the old behavior by default though.

There were problems with:
- arrays in step functions (array were declared with an incorrect syntax)
- the node_loop.c file was wrong in presence of arrays in I/O
- clock that are outputs (a "*" was missing)

to behave as scanf("%d")

(the function that perform this job is actually in rdbg-plugin so that it is shared
with lutin and rdbg)

It generates C code that compile on at least one example.

(to be kind with data plotters).

As far as ldbg is concerned, it only traces the toplevel node, at
call event.

Note that I needed to rename quite a lot of modules to avoid name clashes
between lus2lic.a and ltop.

I've also merged the Verbose module with the one of Lutin so that
they can be shared (there were sharing 95% already).