cakephp/cakephp — pull request #722 by uzyn (2012-07-19 13:02:48+00:00)
Title: Fix URL validation to allow underscores in subdomain.

Allowing underscores in subdomain for URL validation.

References:
http://stackoverflow.com/questions/2180465/can-someone-have-a-subdomain-with-an-underscore-in-it
http://domainkeys.sourceforge.net/underscore.html

The current URL validation invalidates some working URLs that are entered by users, eg. http://liza_ayu.pitas.com