EntitySet: optimze globalBoundingBox calculation
EntitySet: optimze globalBoundingBox calculation

No need to do two separate reductions for MIN and MAX, a single one
would suffice (with negated values).

amccaskey/DataTransferKit,Rombur/DataTransferKit,dalg24/DataTransferKit,amccaskey/DataTransferKit,Rombur/DataTransferKit,amccaskey/DataTransferKit,ORNL-CEES/DataTransferKit,ORNL-CEES/DataTransferKit,ORNL-CEES/DataTransferKit,amccaskey/DataTransferKit,Rombur/DataTransferKit,ORNL-CEES/DataTransferKit,dalg24/DataTransferKit,dalg24/DataTransferKit,dalg24/DataTransferKit,Rombur/DataTransferKit