added a new option -print_reuse that prints clock disjoint variables and reuse policy.

 useful for debugging and carrying correctness proofs to the C code level.
 non trivial result only when option -O 3 or above is activated.


git-svn-id: https://cavale.enseeiht.fr/svn/lustrec/lustre_compiler/trunk@383 041b043f-8d7c-46b2-b46e-ef0dd855326e