bugfix/tests-and-rest

* fixed response bug on put, which is just a temporary solution.
* adapted tests to fail if bug occurs again; 
* fixed restapi return values-> (excluded circular references)
* adapted labels (types now are in second row);

-----------

- [x] finished the code
- [ ] gathered feedback for my changes
- [x] test coverage


| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Tests pass?   | yes
| Fixed tickets | yes
| Doc           | none