Merging changes to README.md from gh-pages
Merge pull request #4 from gvwilson/gh-pages

Switching to redcarpet for rendering.
Updating lesson material imported from THW
Merge branch 'master' of github.com:swcarpentry/bc into gh-pages
IPython Notebooks for the blocks-based intro to Python
Merge branch 'gh-pages' of github.com:swcarpentry/bc into gh-pages