Build type information on first use (load-time), instead of using a hardcoded list

--HG--
branch : dynamiccore2

src/modules/physics/box2d/PolygonShape.cpp

@@ -34,6 +34,8 @@ namespace physics
 namespace box2d
 {
 
+love::Type PolygonShape::type(&Shape::type);
+
 PolygonShape::PolygonShape(b2PolygonShape *p, bool own)
 	: Shape(p, own)
 {