Provide the running test instance to DescriptionProviders

[codecholeric]

When using @CaseDescription with a custom CaseDescriptionProvider, it would be nice if the description method of the CaseDescriptionProvider would receive an instance of the running test. This way it would be possible to provide a description depending on some state of the currently running test instance.

[janschaefer]

The main challenge with this suggestion is that JGiven supports JUnit and TestNG. The question is now if there should be a unified solution or one solution for each framework.