world now uses IVM, is it possible to remove this?

noticed couple of bugs:

• private server you can select a new icon. Old renderer creeps & structures use the new icon, new webGL renderer they use your official screeps icon.
• private server creeps seem to jump when moving? this is with tick rate of 1000:

(hm, a little weird but this creep blinks but only in my recording software, not on my actual screen. Used screenToGif)