Allow copying only top/bottom segments in halReplaceGenome
Allow copying only top/bottom segments in halReplaceGenome

If you know what you're doing.

glennhickey/hal,glennhickey/hal,glennhickey/hal,glennhickey/hal,glennhickey/hal,glennhickey/hal,glennhickey/hal,glennhickey/hal