Implements find or create support for entities with single connection attributes
Fixed bug in predicate string
Moves to an RKMappingOperation-based implementation of find-or-create
Adds compound attribute support
Fixes logging
Adds a dataSource property to RKRelationshipConnectionOperation to facilitate recursive find-or-create operations
Removes unnecessary getter and @synthesize call
Adds optional NSPredicate complexPredicate property to RKEntityMapping
Adds complexPredicate support for cases where combining identificationAttributes with AND may not be appropriate