Landscape-Service generates new Ids and does not use and update old instances

[Alexander-Krause-Glau]

Seems like there is a major bug in the landscape-service that results in using new entities with new Ids (or updating the Id of old entities, not sure) instead of simply updating old values of known entities.

As a result the frontend thinks it gets new records (due to the new id) and the Ember Store grows and eventually the browser crashes due to EXCEPTION_STACK_OVERFLOW.

Todo Fix id handling; Old entities should be reused.