Updated changelog and bumped version to 5.1.1

Fixed a test breaking PyPy and restored support for RST docs

Decorating builtin functions

Fixed doctest breaking in Python 3.5

Tested docstring preservation

Added another test

Markdown fix

Fixed setup.cfg

Merge pull request #100 from Amli/fix-setup-for-python-below-35

Fix python version in setup for release 5.0.0

Fixed test