Bug 1030972 - Import tasks from Bugzilla

@bobsilverberg @Osmose r?
Yes, we do want to be able to clone a batch. I thought maybe that was even supposed to be included in this feature, but I guess it can wait. We did talk about the idea of a Task Template which was attached to the batch - what happened to that idea? Each Task created is linked to the batch, right? So I guess we can infer the batch properties from a Task, except that a Task could be edited after it has been created, so that won't always be accurate. I do think we should have a way of being able to recreate a batch, exactly as it was when it was run, so that would mean saving something.