Illegal JID when configuring a created MUC room

A snippet of the room configuration that is received by Openfire is this:

I'm not sure where that second, empty value element originates, but that's the one causing the problem.

Earlier today, I've committed a change that:

• includes a new version of Tinder, that, apart from the more verbose debug messages () also has a new utility method that simplifies working with bare jid objects ().

• adds more defensive code to Openfire, where collections of JIDs are being processed. Empty values are now ignored.

The above changes prevent the problem from occurring, as the empty value element is ignored.

With latest tinder we get

results in this traceback on trunk