RaycastResult: Ray is not a needed require

When importing `Ray`, you end up with circular dependencies. Since it's not needed here, we can safely remove it.

Author: RobLoach

src/collision/RaycastResult.js

@@ -1,5 +1,4 @@
 var vec2 = require('../math/vec2');
-var Ray = require('../collision/Ray');
 
 module.exports = RaycastResult;
 
@@ -131,4 +130,4 @@ RaycastResult.prototype.set = function(
 	this.body = body;
 	this.fraction = fraction;
 	this.faceIndex = faceIndex;
-};
+};