Update repo ref and add zenburn css
Add zenburn css for code blocks
Merge branch 'master' of github.com:samtsai/reveal-md

* 'master' of github.com:samtsai/reveal-md:
  Update repo ref and add zenburn css
Revert repo ref back to originator
Merge pull request #4 from samtsai/master

Add zenburn.css for code block styles