Use hashes for Markdown levels in top level README.md.
Use hashes for Markdown levels in top level README.md.

For consistency.

5x5x5x5/ReproTutorial,5x5x5x5/ReproTutorial,reproducible-research/scipy-tutorial-2014,reproducible-research/scipy-tutorial-2014,reproducible-research/scipy-tutorial-2014,5x5x5x5/ReproTutorial