Rewrote -serializationGetter/SetterForProperty: in raw C
Rewrote -serializationGetter/SetterForProperty: in raw C

This cuts 1,5s to -testGoToOldestAndNewestNodesInHistoryWithManyPropertiesPerEntity.

For going back to the last node in this test, the time goes down from 2.6s to 2.1s.

etoile/CoreObject,etoile/CoreObject,etoile/CoreObject,etoile/CoreObject