add to support china (The People\'s Republic of China)zip code.

The China zip code list can see in http://en.wikipedia.org/wiki/List_of_postal_codes_in_China.
It's not good enough.
For example, based on http://en.wikipedia.org/wiki/List_of_postal_codes_in_China, ```170000``` passes the ```^\d{6}$``` pattern, but it's not valid China postal code.