AT-specific Form helpers
Austrian Social Security numbers are composed of a 4 digits and 6 digits field. The latter represents in most cases the person’s birthdate while the first 4 digits represent a 3-digits counter and a one-digit checksum.
The 6-digits field can also differ from the person’s birthdate if the 3-digits counter suffered an overflow.
This code is based on information available on http://de.wikipedia.org/wiki/Sozialversicherungsnummer#.C3.96sterreich
A Select widget that uses a list of AT states as its choices.
A form field that validates its input is an Austrian postcode.
Accepts 4 digits (first digit must be greater than 0).
A list of Austrian states according to https://en.wikipedia.org/wiki/States_of_Austria