function SAPBroadphase(world){
    Broadphase.apply(this);

    /**
     * List of bodies currently in the broadphase.
     * @property axisList
     * @type {Array}
     */
    this.axisList = [];

    /**
     * The world to search in.
     * @property world
     * @type {World}
     */
    this.world = null;

    /**
     * Axis to sort the bodies along. Set to 0 for x axis, and 1 for y axis. For best performance, choose an axis that the bodies are spread out more on.
     * @property axisIndex
     * @type {Number}
     */
    this.axisIndex = 0;

    var axisList = this.axisList;

    this._addBodyHandler = function(e){
        axisList.push(e.body);
    };

    this._removeBodyHandler = function(e){
        var idx = axisList.indexOf(e.body);
        if(idx !== -1){
            axisList.splice(idx,1);
        }
    };

    if(world){
        this.setWorld(world);
    }
}
Sweep and prune broadphase along one axis.

@class SAPBroadphase
@constructor
@param {World} [world]
@extends Broadphase