Create compatibility matrix test.

We need to create the compatibility cross matrix test. We should strive for maximal compatibility. This means:
An older client should be able to run all tests against any newer server.
A newer client should be able to run all tests against any older server except if the test is using newer functionality. We should add an annotation (or something equivalent) for tests that explicitly require newer server support. In those cases, the client library should fail with a very obvious error.
We should try very hard to provide this guarantee starting with GA (and ideally before, with later stage betas).