database of robots.txt-derived permissions

 WWW::RobotRules parses /robots.txt files as specified in "A Standard for
 Robot Exclusion", at <http://www.robotstxt.org/wc/norobots.html>. Webmasters
 can use the /robots.txt file to forbid conforming robots from accessing parts
 of their web site.
 .
 The parsed files are kept in a WWW::RobotRules object, and this object
 provides methods to check if access to a given URL is prohibited. The same
 WWW::RobotRules object can be used for one or more parsed /robots.txt files