Remove this -- dealt with in the Rakefile
Update with the correct links
New posts on open source licenses

Thanks to Ted Han (@knowtheory), Jacob Kaplan-Moss (@jacobian), and
Miranda Mulligan (not on GitHub‽) for feedback on early versions of
this.  The full draft and comments are in [this gist][].

[this gist]: https://gist.github.com/tswicegood/c3f1156b06e5f771173d
Tools vs Materials post