- skip some tests if Storable not found (for old perls).
  versions ok: 2.21, 2.20, 2.19, 2.18
  perls found in: 5.11.0, 5.10.1, 5.10.0, 5.8.8, 5.8.9p35104, 5.8.9, 5.8.8, 5.6.2

- "passing argument 3 of 'Perl_newXS' discards qualifiers
   from pointer target type". is this still a problem?

- clean up!

- figure out how to call perl's exp(), log() and getpid() functions.

