Bump version to 0.6.1

Merge pull request #46 from mutpy/externalize-test-runner

Externalize test runner and add experimental pytest support

Bump version to 0.5.1 - fixed PyPI builds

Bump version to 0.5.0

Pass module name instead of file name. Put all HTML mutants file into…

… separate directory.

Merge.

Small refactor changes.

Added simple setup.py file.