A few README tweaks (#73) (#79)

* Add a paragraph at the top for users, not builders, of Python.

* Use nicer rst url syntax to avoid borking paragraphs in the plain text.

Contributed by Ned Batchelder @nedbat

(cherry picked from commit 3cdbd68ce8230cff1afb67472b96fbfa7f047e32)
1 file changed