Don't check isExcluded up front

Controls that are not initially displayed on the page don't ever get validated after displaying them.  isExcluded is checked at validation time, so it is safe to just skip this check.
Make dash optional in US zip codes
Added countryfield option on zip code

The countryfield option enables checking another field for the country code.  This allows the validation to be dynamic based on the user's selection.
Merge pull request #447 from AlaskanShade/master

Zip code and isExcluded updates