Add demo notebook

[kgryte]

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read and understand the Code of Conduct.
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• Searched for existing issues and pull requests before submitting this pull request.
• Filed an issue (or an issue already existed) prior to submitting this pull request.
• Submitted against master branch.

Description

What is the purpose of this pull request?

This pull request:

• adds a basic demo notebook which can be used for experimenting with commenting within a notebook environment.

Related Issues

Does this pull request have any related issues?

This pull request:

• partially addresses the Binder requirement discussed in NYU Handoff #42.

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

No.