* Add more recipes to the cook book
    * XPath tutorial and recipes
  * Add an 'attributes' instruction that reads only the next element and it's attributes
  * Improve speed of the module through XS
  * Validate the configuration prior to starting processing so errors in there don't show up in the
    middle of a long job
  * Support using a regex to match a path in iterate_at()
  * Make XPath optional supporting not having Tree::XPathEngine installed for the rest of
    the module to work