Merge pull request #52 from ruby-processing/master

Update README.md
Update LICENSE
Updated Readme for chapter 5 to refer to Box2D for Processing rather than PBox2D
Merge pull request #53 from liam-middlebrook/rename/PBox2D

Updated Readme
Update README.md

added the port of some of the box2d examples to paper.js
Merge pull request #54 from hardmaru/patch-1

Update README.md
Merge pull request #1 from shiffman/master

update