gravity function not setting gravity, possible fix provided

[selticesystems]

The problem is with:

gravity: function(value) {
    if (value !== undefined) {              
        this._world.SetGravity(new b2Vec2(value.x, value.y));
    }
    var v = this._world.GetGravity();
    return {x: v.x, y: v.y};
},

I had to change

this._world.SetGravity(new b2Vec2(0, value));

to

this._world.SetGravity(new b2Vec2(value.x, value.y));

It asks for {x,y} but if you send in {x: 0, y: 20} for example, it thinks y is now an object until the above fix is applied.