when is version 13 scheduled to be released?
Well, mellis can speak for himself and I know he's working on the 0013 release process right now.
But I'll say generally with Open Source projects, the answer to this kind of question is often, "when it's ready." There's no fixed schedule for many projects, and any hiccup found at the last second just takes a little time to fix it up. So when it comes to anticipating a new version, I just sit on my hands and refrain from asking, "is it done yet!?" 
It's kind of like driving south on I-5 destined for Disneyland, with the kids in back asking, are we there yet? are we there yet? Don't make me stop this car kids. ;D
Lefty