cosmetics
cometics
improve exception messages of ParentIdGenerator
fix tests
detect when someone attempts to map the identifier to multiple differnt properties
Merge pull request #239 from doctrine/detect_duplicate_id_mapping

detect when someone attempts to map the identifier to multiple different properties
Renamed name types
Merge branch 'master' of git://github.com/doctrine/phpcr-odm into patch-item-not-found-version