Also call render from the user thread

Someone moved the call to render out of the thread loop and into
the texture update function. Same rationale for putting it back.
It should not overlap other user code and it should be possible
to detect if the user code hangs.

32blit-sdl/System.cpp

@@ -269,15 +269,15 @@ void System::loop()
 	blit::joystick.y = shadow_joystick[1];
 	SDL_UnlockMutex(m_input);
 	blit::tick(::now());
-    blit_multiplayer->update();
+	blit::render(::now());
+	blit_multiplayer->update();
 }
 
 Uint32 System::mode() {
 	return _mode;
 }
 
 void System::update_texture(SDL_Texture *texture) {
-	blit::render(::now());
 	if (_mode == blit::ScreenMode::lores) {
 		SDL_UpdateTexture(texture, nullptr, __fb_lores.data, 160 * 3);
 	}