Changed World:update(dt) to default to Box2D's recommended 3 internal position iterations instead of 6. Added a new variant World:update(dt, velocityiterations, positioniterations) which lets you specify the number of velocity and position iterations Box2D performs when updating the world. The defaults are 8 and 3 respectively, higher numbers increase precision and reduce performance.

Resolves issue #1135.

--HG--
branch : minor

src/modules/physics/box2d/World.h

@@ -131,6 +131,7 @@ public:
 	 * @param dt The timestep.
 	 **/
 	void update(float dt);
+	void update(float dt, int velocityIterations, int positionIterations);
 
 	// From b2ContactListener
 	void BeginContact(b2Contact *contact);