Adagrid validation orderer

[tbenthompson]

The use of global_target and max_target in the orderer means that we can't change those values during an adagrid run. Figure out a different way of doing the ordering!

[tbenthompson]

Ideally we would have a single ordering key. This could still be a composite key but it could be structured by using the upper 16/32 bits for half the key and the lower 16/32 bits for the other half of the key.