Populate correct defaults

It's a bit sad that it has to be done this way, but I cannot come up with a better way.
It would be nice to have per folder defaults, but that means we either need to copy and modify the XML parser
or do it in some crazy way.

What's even more sad, is that now you have tu provide these default values as part of the `/config` call as otherwise you'll end up in a configuration which doesn't work.

Perhaps I should do just:
`max(p.copiers, 1)`, `max(p.pullers, 16)`, `max(p.finishers, 1)` in the puller?