Use the Sphinx doctest builder

This allows us to test our documentation snippets using the standard
"doctest" utility.
Merge pull request #43 from tiran/master

Fix spelling of my name
Fix __author__
Merge pull request #42 from dstufft/doctests

Use the Sphinx doctest builder
Merge pull request #44 from hynek/fix-__about__

Fix __author__
Also mention that other packages miss python3 support
Nit for Hynek
Merge pull request #46 from alex/another-reason

Also mention that other packages miss python3 support