* add back ability to create transform with loader
* change 'samples' -> 'examples' for tfds wrapper to match tfds naming
* add support for specifying feature names for input and target in tfds wrapper
* add class_to_idx for image classification datasets in tfds wrapper
* add accumulate_type to avg meters and metrics to allow float32 or float64 accumulation control with lower prec data
* minor cleanup, log output rate prev and avg
* support some torchvision datasets
* improvements to TFDS wrapper for subsplit handling (fix#942), shuffle seed
* add class-map support to train (fix#957)
* Add parser/dataset factory methods for more flexible dataset & parser creation
* Add dataset parser that wraps TFDS image classification datasets
* Tweak num_classes handling bug for 21k models
* Add initial deit models so they can be benchmarked in next csv results runs