SECURITY ALERT: Corrected regular expressions for URL and email fields.

      Certain email addresses/URLs could trigger a catastrophic backtracking
situation, causing 100% CPU and server overload. If deliberately triggered, this
could be the basis of a denial-of-service attack.

This security vulnerability was disclosed in public, so we're skipping our
normal security release process to get the fix out as soon as possible.

This is a security related update. A full announcement will follow.



git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.0.X@11605 bcc190cf-cafb-0310-a4f2-bffc1f526a37