fix mouse joint, draw center of mass, cleanup

include/bounce/dynamics/island.h

@@ -29,27 +29,6 @@ struct b3Velocity;
 struct b3Position;
 struct b3Profile;
 
-struct b3IslandBody
-{
-	b3Body* b;
-	u32 id;
-	bool visited;
-};
-
-struct b3IslandJoint
-{
-	b3Joint* j;
-	u32 id;
-	bool visited;
-};
-
-struct b3IslandContact
-{
-	b3Contact* c;
-	u32 id;
-	bool visited;
-};
-
 class b3Island 
 {
 public :

include/bounce/dynamics/joints/mouse_joint.h

@@ -80,6 +80,7 @@ private:
 	u32 m_indexB;
 	float32 m_mB;
 	b3Mat33 m_iB;
+	b3Vec3 m_localCenterB;
 	b3Mat33 m_mass;
 	b3Vec3 m_rB;
 	b3Vec3 m_impulse;