* Add training to batchnorm with exponential moving average
* Add more checks to batch norm
* Resolve some review comments
* Add with_momentum varients of `new` methods
* Add check for range of momentum variable; update batch norm test
* Run cargo fmt
* Add back num_features parameter
* Format; tiny simplification
* Some fixes for yolo-v3.
* Use the running stats for inference in the batch-norm layer.
* Get some proper predictions for yolo.
* Avoid the quadratic insertion.
