Provide simple, clean notebook to help people get started working with the data

[smasis001]

Brad and I were trying to figure this out to no avail. Please provide a jupyter notebook with some examples. And a free repo with some sample images for training

[gsganden]

See #51. I agree that this is a big problem -- it's hard to do anything on this project without a data set to work with.

[gsganden]

@smasis001 there is still room for improvement, but I think this repo is much more usable now. I'd love to get your feedback if you get a chance to take another look.

[smasis001]

@gsganden I have updated my fork and I will take another look. Thanks for keeping me in the loop.

[gsganden]

I refined the title to eliminate overlap with #11.

[gsganden]

https://github.com/UptakeOpenSource/autofocus/blob/master/autofocus/train_model/train_multilabel_model.ipynb can fulfill this role to some extent, but it's not optimized to help people get started.