Added enumerations
Added countries and states to enumerations.
Began recurring payment class and recurring payment filter class.
Finished RecurringPayment class.
Added a module to generate state methods

  These state methods correspond to a constant that is set to the
  state's id in Paysimple. We dynamically generate two methods for each
  state: the state abbreviation and state name.
Merge branch 'master' of github.com:/CTA/PS into experiment

Conflicts:
	lib/ps/response.rb