Update GTWAOFQuadStore to insert quads into an SPOG B+ tree index.
Improved precision of GTWAOFQuadStore lastModifiedDate method by using the B+ tree LCA mtime.
Updated GTWAOFUpdateContext to fully implement the GTWAOF protocol, allowing reading uncommitted pages during an update.
Updated GTWAOFQuadStore to add values to the SPOG B+ tree within a single update context.
Created GTWAOFBackedObject protocol to aid in the setting of the aof ivar on update commit.