[library] use Storable 2.13; protect against too old Storable-2.09, which cannot overload stringify
[library] use Storable 2.13; protect against too old Storable-2.09, which cannot overload stringify

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@31585 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot