Saw pit - Oxen never deliver

[Beric01]

Oxen will never deliver to the saw pit as long as there are other jobs for them (i.e. construction, fallen trees, etc.), and there is no way to prioritize the saw pit for delivery. The only way is to do a manual oxen assignment to the saw pit temporarily, and then you can switch it back later. Would like so way to have this handled automatically so we don't have to oxen micromanage early to make planks.