Update Examples Documentation to Cover Dataloaders / Batching

[palisadoes]

Though there is some information on how to implement dataloaders in test_batching.py, the sample code in the examples directory lacks examples of how to do it.

My original code is based on that in the examples directory. I have been trying to use test_batching.py to get batching working without much success. If I got it to work I would have submitted a PR.

This is a significant new feature for the code base and it would be excellent to have definitive examples in the repo.