Started revamp of the Tilemap system. Also removed old 'Advanced Physics' and dropped in p2.js which is what I hope we'll eventually use.

src/physics/advanced/shapes/Particle.js

@@ -0,0 +1,22 @@
+var Shape = require('./Shape');
+
+module.exports = Particle;
+
+/**
+ * Particle shape class.
+ * @class Particle
+ * @constructor
+ * @extends {Shape}
+ */
+function Particle(){
+    Shape.call(this,Shape.PARTICLE);
+};
+Particle.prototype = new Shape();
+Particle.prototype.computeMomentOfInertia = function(mass){
+    return 0; // Can't rotate a particle
+};
+
+Particle.prototype.updateBoundingRadius = function(){
+    this.boundingRadius = 0;
+};
+