Add int.NumOf realization.

Signed-off-by: Claude Marche <Claude.Marche@inria.fr>

Conflicts:
	examples/hackers-delight/why3session.xml
	examples/hackers-delight/why3shapes.gz
	theories/bv.why

- generation in the makefile
- proofs done
Remove complex axioms from Pow2int in bv.why.
Add guards in rotates axioms in bv.why.

This should restore the current failing replay of nightly bench

This allows us to produce monomorphic instances for the symbols
in "lskept" even if the corresponding ground types (e.g., arrays)
do not occur directly in the goal/task, because they are hidden
inside some supertypes.

since results are better with the Why3 axiomatic version