Create a window with the given title, width and height, also apply the flags

Property definitions

sdl2 $ SDLWindow :: new
	# Create a window with the given `title`, `width` and `height`, also apply the `flags`
	new (title: CString, width, height: Int, flags: SDLWindowFlags) `{
		return SDL_CreateWindow(title,
			SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
			width, height, flags);
	`}
lib/sdl2/sdl2_base.nit:141,2--146,3