Further advancements on aggregate validation.
Completed basic implementation of validation for linked entities and collections.
Added some unit tests
Added remaining tests for new entity validation harness.
Refactored PropertyValidator, EntityValidator and Collection validator to be just Property, Entity and Collection which is much better for clarity.
Changed methods of adding validators to linked entities and collections.
Added notEmpty flag to linked Entity and Collection along seth accessors indicating that additional check is required for being not empty.
Added checks for linked entities and collection being not empty.
Merge branch 'refs/heads/Feature/AggregateValidation' into release