OliverAh

After the training (`for i in range(50):`) the model mode is switched to `model.eval()`. Then after activating the `with ...verbose_linalg():` context, it is switched back to `model.train()` just to be...

I did, using 3 runs each. Without switching back and forth it is approx. 5% faster, when **not specifying the contexts** `(with gpytorch.settings...)`. When specifying the contexts, the runtime seemed...