Don't allow extra characters surrounding valid postal codes

  * "123456" was previously considered a valid US zip code, as it
    contains the valid "12345" zip code
  * Regenerates postal_codes.yml based on updated regexp_parser gem
  * Provides for a way to both match single and multiple zip codes
Different attempt at 1.8.7 support
Merge pull request #135 from bonobos/fix/postal-codes-extra-chars

Don't allow extra characters surrounding valid postal codes