Added love.graphics.origin(): resets the coordinate system (replaces the current transformation matrix with the identity)

--HG--
branch : love.graphics.origin

src/modules/graphics/opengl/wrap_Graphics.h

@@ -110,6 +110,7 @@ int w_rotate(lua_State *L);
 int w_scale(lua_State *L);
 int w_translate(lua_State *L);
 int w_shear(lua_State *L);
+int w_origin(lua_State *L);
 int w_hasFocus(lua_State *L);
 extern "C" LOVE_EXPORT int luaopen_love_graphics(lua_State *L);