added 6 digit support to URL pattern

Found a url that gives an error because it has six instead of seven digits at the end.

This url - http://blip.tv/undressedtv/episode-18-three-in-the-van-991960 gave a no url service error because it has a 6 digit number instead of seven like all the rest.

But I tested the video and when added to the pattern the video will not play with service, but no error in system log and video plays on bliptv website, so not sure if more coding may be needed. Just wanting to prevent error with a show not producing results due to one bad video url causing errors.