Use the Sphinx doctest builder

This allows us to test our documentation snippets using the standard
"doctest" utility.
Fix spelling of my name
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__
Merge branch 'master' into simple-symmetric-encryption