make the regular expression for "link href=" a bit more robust: it now handles
http://research.swtch.com/feed.atom correctly.
Give "link" URLs priority over "guid" URLs
Moved the call to check for "link href" before the call to check for
"link", since the latter modifies the string.
Update the README file to describe the new features and to make it
a bit less terse.
Lengthen the timeout delay.  (Some feeds were getting chopped off at the middle.)