xmpp api setting

Thanks for this great module. I think I'm like a lot of people I've been seeing comments from who have a Drupal site and access to an XMPP server but don't necessarily have the chops to administer it. I use OpenFire, and all I really want to do is give users the option for Drupal messages to go to IM. And it was really, really easy once I got over this bug:

The XMPP Framework settings' XMPP API setting appears to default to 'XMPP API', but after installing the module, by default, no value is set.

The attached patch to adds a blank <option> to the drop-down form when the value is not set. I know it is only adding 3 lines of code, and one if them is }, but patches are so much more fun.

Some additional ways to help people figure this out might be giving the setting a different name from one of the modules it can be set to, giving a warning to admins if this isn't set, and adding a 'test' button. I don't have the energy to patch all of these right now, but am willing to work on these if you are interested.