updated demos, add CX WIP notebook

[colleenXu]

Will refer to this pull request in the issues I raise soon. Updated demos with fixes and more explanation, added my notebook that includes drafts of explanations/documentation and demonstrations of issues.

[andrewsu]

Lots of good issues raised here. My only comment is that I don't think we should add the CX_WIP notebook to the base branch. I think that notebook is super useful to illustrating the various issues and we should use it as a basis for improving code/notebooks/documentation. But adding that notebook itself into the base branch I think might create more confusion for potential users...

[colleenXu]

Perhaps I can keep CX_WIP in my fork or a side branch instead. It does demo the issues that I raise, so I'd like these issues to link to it wherever it ultimately goes.

What do you think of the changes to the PREDICT and EXPLAIN demo notebooks that are also in this request?

[andrewsu]

Yes, agreed on keeping CX_WIP in a fork or branch. I haven't looked at the PREDICT/EXPLAIN demo notebook changes -- I'll defer to @kevinxin90 on those...

[kevinxin90]

@colleenXu So pls first revert ur commits for your WIP notebook, meanwhile I will take a look at ur other notebooks. It will take some time, since it's very hard to understand the changes you make for a long jupyter notebook on github.

[ravila4]

Hi, I recently found this tool that could be useful for reviewing Jupyter notebook diffs: https://github.com/jupyter/nbdime