Separate rendering and other features in smoke testing

So far, we test the algorithms and environments in the smoke tests. We do this now also with rendering, and it seems that this slows down the testing process a lot. The following would be good:

• Change the testing of algorithms and environments so that these tests do not render anything
• Add an additional rendering test
• Also, add an additional test for storing and loading a model, possible for different algorithm.
• Add additional tests for potential other future features