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/solver/Solver.js

@@ -0,0 +1,65 @@
+var Utils = require('../utils/Utils');
+
+module.exports = Solver;
+
+/**
+ * Base class for constraint solvers.
+ * @class Solver
+ * @constructor
+ */
+function Solver(){
+
+    /**
+     * Current equations in the solver.
+     *
+     * @property equations
+     * @type {Array}
+     */
+    this.equations = [];
+};
+
+Solver.prototype.solve = function(dt,world){
+    throw new Error("Solver.solve should be implemented by subclasses!");
+};
+
+/**
+ * Add an equation to be solved.
+ *
+ * @method addEquation
+ * @param {Equation} eq
+ */
+Solver.prototype.addEquation = function(eq){
+    this.equations.push(eq);
+};
+
+/**
+ * Add equations. Same as .addEquation, but this time the argument is an array of Equations
+ *
+ * @method addEquations
+ * @param {Array} eqs
+ */
+Solver.prototype.addEquations = function(eqs){
+    Utils.appendArray(this.equations,eqs);
+};
+
+/**
+ * Remove an equation.
+ *
+ * @method removeEquation
+ * @param {Equation} eq
+ */
+Solver.prototype.removeEquation = function(eq){
+    var i = this.equations.indexOf(eq);
+    if(i!=-1)
+        this.equations.splice(i,1);
+};
+
+/**
+ * Remove all currently added equations.
+ *
+ * @method removeAllEquations
+ */
+Solver.prototype.removeAllEquations = function(){
+    this.equations.length=0;
+};
+