Added differential drive robot platform example - still has issues
Added nbviewer link to readme
Fixed simulation bugs, added controller design
Final Edits:

- Drew up a new SVG diagram
- Removed the controller portion of the example. It was poorly
done, and making it correct would make the example far too long
- Added intro and conclusion for blog post
- Grammar checks
Bug fix, formatting issues
Constraints were mislabeled as holonomic. Fixed
Merge pull request #18 from jcrist/master

Add example of Differential Drive Robot Dynamics