add example programs

Description

Copied example programs from https://git.barrett.com/burt/software/burt-csharp-examples, preserving entire commit history from devel branch of that repo. No changes to the actual programs here. Minor update to the readme to mention the examples.

What to focus on

• put content here.

Reviewers

• @cw
• @amyblank
• @bz
• @ps
• @alexluleme

Resources

Issues

What issues does this fix?

• Fixes #issue-number