Add initial version of writeUnsignedAP

Only the trivial case is tested/implemented.
Update implementation of writeUnsignedAP for 2nd test.
Add third test for writeUnsignedAP
Add 4th test for writeUnsignedAP
Add 5th test for writeUnsignedAP
Finish tests for writeUnsignedAP
Merge pull request #2 from michaelgwelch/addAPWrites

Add writeUnsignedAP