Support for weblogs.com XML-RPC ping

We have added support in Movable Type to talk to the new weblogs.com XML-RPC ping interface (more information). Rather than automatically checking for changes in all registered blogs (the old behavior), weblogs.com now requires that an XML-RPC ping be sent to mark the blog as changed.

We have added support for this new interface, and have written instructions for setting up XML-RPC ping support in MT. (Note: the instructions assume that you have already installed version 1.1 of Movable Type, so you should do that first.)