#11 Update to protocol v15, fixes chat room support

[Javier Kohen]

This patch against version 0.61 updates the protocol used by the library to version 15 so that chat rooms work again.

Beware, it only includes the minimum changes to fix that particular feature. If your client does things like using the contact list, it will break, because the protocol changed.

I'll let someone else post a patch to fix those, though, I only made this patch for a friend who doesn't need that and my own copy of jYMSG has been modified beyond recognition, so creating a more complete patch is out of the question.

[Javier Kohen]