Make the script check for an argument.  Remove obsolete node example.  Fix error message
Add a reference on how to run with Node
disable undefined XHR warning under Node

This gets rid of the warning:

    Error stringifying object: [ReferenceError: XMLHttpRequest is not
defined]
Merge pull request #45 from shamrin/disable-node-xhr-warning

disable undefined XHR warning under Node
don't fail inside doctest on undefined exceptions

This happens when test forgets `new` in  `throw Error;`