Version 1.0 (March 11, 2012)
----------------------------

* gaps in 2004 Civicspace data filled by data 
  compiled by http://federalgovernmentzipcodes.us
* out-of-date timezone fields removed from 'zipcode' data.frame
* original 'zipcode' data.frame available as 'zipcode.civicspace'


Version 0.21
------------

* updated license descriptor to include newly-supported "CC BY-SA 2.0"


Version 0.2
-----------

* clean.zipcodes function now returns NAs for blank and whitespace-only
  inputs as well

* Added clearer warning to data's documentation that no updates have been 
  made since 2004's publication

* Cleaned up several aspects of the documentation and added sample output
  to each example
