Changes

::*By now, we only focus on cleaning American patents.

::U.S. post code follows the pattern [five digits - four digits]. In this way, U.S. patents can be extracted by searching for post code with regular expression.

::The extracted records are stored in table ptoassigneend_missus.

::* The ultimate post code and zip regex for other countries besides U.S. can be found here:

http://stackoverflow.com/questions/578406/what-is-the-ultimate-postal-code-and-zip-regex