keypaths work accross to-many relationships with relationship(…)
Renamed relationship marco, now works with @ and changed to 3/4 arg verisons
added collectionOperators
Made collectionKeypath use only @keypath and documented. Removed collectionOperators
Merge branch 'master' into collection-keypath
Add unit tests for @collectionKeypath
Disable -Wundeclared-selector for the project
Merge branch 'collection-keypath' (pull request #34)