• Start detecting a few robots we weren't detecting before
  ('verify' or 'analyze' in the name, or +https: beginning
  the URL) (andrewmoise)
  
• Stop including the version in robot_string() in some
  cases (andrewmoise)
  
• Start returning undef instead of 0 for robot() if there's
  no robot (andrewmoise)
  
• Fix _version() documentation for robot, os, and version not
  to make formatting garbage in the output, and to be
  consistent (andrewmoise)