Add the modes3x2 exemple of Pascal (its version + a la V6 version).

Fix the doc wrt the merge exemple (the tex was refering to a
non-existant file).

Actually, it was a misunderstanding of mine (R1) ; the behavior was consistent
with the lv6 doc, but not with the v4 behavior...

Indeed, # means "at most 1 among n", not "exactly one among n" as I tought...

nb : do not work for lv4/ec mode

'-' replaced by 'm', '.' by 'd',
(see "correct_num_string" in LicDump.ml)

maintaining (ugly and error-prone) hash tables.

That change revealed an untriggered bug in EvalClock.check_args: it was wrong
to add in subst the substitutions made of the parameters and the arguments (it
is enough to unify the clocks of the pars and of the args). For instance, consider
the node (in should_work/clock/clock.lus)

   node clock5(x :  bool; y:  bool when x; z: bool when y)

and the call

  z2 = clock5(a, b when a, c when e);

I was adding y/b in the subst, which was wrong.

Other minor changes:
 - move const_to_val_eff from Eff to UnifyClock.
 - GetEff.translate_val_exp now returns a substitution, in order to be able
   to unify clock vars and propagate the resulting substitution.

constants that  are not  on the base  clock, add the  suitable "when"
statement if it was not present  in the source code (the lic (and the
ec/lv4) backend  does not  perform such kind  of clock  inference for
constants.

(--inline-iterators) to activate it.

nb : do not inline completely nested iterator calls (yet, cf TODO).