Fixed two cases of inefficient usage of the lua api

src/modules/graphics/opengl/wrap_Graphics.cpp

@@ -295,12 +295,8 @@ namespace opengl
 	int w_newFramebuffer(lua_State * L)
 	{
 		// check if width and height are given. else default to screen dimensions.
-		int width  = instance->getWidth();
-		int height = instance->getHeight();
-		if (lua_gettop(L) >= 2) {
-			width = luaL_optint(L, 1, instance->getWidth());
-			height = luaL_optint(L, 2, instance->getHeight());
-		}
+		int width  = luaL_optint(L, 1, instance->getWidth());
+		int height = luaL_optint(L, 2, instance->getHeight());
 		glGetError(); // clear opengl error flag
 		Framebuffer * framebuffer = instance->newFramebuffer(width, height);
 
@@ -614,7 +610,7 @@ namespace opengl
 	int w_setRenderTarget(lua_State * L)
 	{
 		// called with nil or none -> reset to default buffer
-		if (lua_isnone(L,1) || lua_isnil(L, 1)) {
+		if (lua_isnoneornil(L,1)) {
 			Framebuffer::bindDefaultBuffer();
 			return 0;
 		}