Make ignite utils public

When using a dataset which returns a tuple of more than 2 values, you have to implement your own _prepare_batch function. Let’s say we’re using this function:

def _prepare_batch(batch, dev=None, non_blocking=False):
    x, instance, boxes = batch

    return (convert_tensor(x, device=dev, non_blocking=non_blocking),
            convert_tensor(instance, device=dev, non_blocking=non_blocking),
            convert_tensor(boxes, device=dev, non_blocking=non_blocking))

As in the original _prepare_batch function used in create_supervised_trainer we’re using the convert_tensor function. This function is located in _utils.py resulting in a protected member access warning. This file has some useful and commonly used methods, so it would be nice if it was public instead.

[vfdev-5]

@anmolsjoshi thanks! my bad, I deleted fork’s branch and that closed the PR. I thought we’ve merged it.

[anmolsjoshi]

@vfdev-5 any reason #396 was closed?