Log Message:
Update to 1.18:

1.18 -- Fri Nov 25 09:30:29 CST 2005

Bug Fixes
  * Fix pure-perl version of refaddr to avoid blessing an un-blessed reference
  * Fix memory leak in first() and reduce()
  * Pure perl version of looks_like_number now matches XS version for
    references and undef. It will now return undef

Enhancements
  * Support for using XSLoader instead of DynaLoader
  * Use new multicall API