…pipeline.

Cache can now be disabled using the `disable_cache` parameter. Added support for fitting and transforming using the same class instance. Simplified the composite pattern for transformers.

Transformer steps in pipeline needs the `fit=` parameter. Reusing the same transformer will count towards the cache limit unless a different `cache_group` is specified. Please refer to the `Australia Rain Classification.ipynb` for examples.

… refactoring the `LRUCacheMixin`.

…and better SageMaker support.

Arrow file format is no longer used for storing output in the cache.