fix ps->go = false;

initial commit: call the `playanim_window_open` only once

immInit should only be called once per application.
However, immediate mode only works if a GHOST window is created.
But every time you drop a video in the anim player, `GHOST_DisposeWindow` is called and a new window is created next. Forcing destroy and init a new immediate mode context :

This patch changes the order of things. And call `GHOST_SetClientSize` intead `GHOST_CreateSystem`, `GHOST_CreateEventConsumer`, `GHOST_AddEventConsumer` and `playanim_window_open`.