Implement UQADD8, UQADD16, UQSUB16, UQASX, and UQSAX

Puts the rest of the UQ* 'family' in place.
Merge pull request #46 from lioncash/qops

Implement UQADD8, UQADD16, UQSUB16, UQASX, and UQSAX