This PR
- only prints train_loop info strings (e.g. `train_loop_utils.py:298 -- Moving model to device: cpu`) for rank 0 workers for torch
- renames `BaseWorkerMixin` to `RayTrainWorker` as the name comes up often in output and is more meaningful
Signed-off-by: Kai Fricke <kai@anyscale.com>
As the integration logging callbacks are commonly used with AIR Trainers, they should be moved from the tune package to the air package. The old imports will still work, but raise a deprecation warning.
The package "ml" should be renamed to "air".
Main question: Keep a `ml.py` with `from ray.air import *` for some level of backwards compatibility?
I'd go for no to force people to use the new structure.
