Adding .gitignore.
.mailmap: Standardize identifiers for Lynne and Matt
Adding some useful developer info and links to the README.

Signed-off-by: Matt Davis <jiffyclub@gmail.com>
Adding contributing guidelines.

Includes license, workflow, and file formats sections.
README.md: Line wrapping and reference-style links

This makes the README easier to read in a terminal or editor, while
leaving the Markdown output unchanged.
Added CC license.
Removed cruft.
Update LICENSE.md
Ignore weird mac DS_Store files.
.mailmap: standardize identifiers for Joshua, Katy, Matt, and Sri
Conversion of all rst to corresponding markdown files

We use git-flavoured markdown
instructor.md: Move README.md to instructor.md

This is instructor-facing content.  We still need an inspirational
blurb for the student-facing README.