Did not get to finish all refactoring or even compile this, I'll continue later

Also adjust margins to better match other HUD stuff

Pros: fuckin SMOOTH effect especially for 256-color sw
Cons: might lose the intended color distortion, maybe
not a great idea for FPS
Conclusion: put it behind an ifdef for now

I don't care enough about supporting old replays, and
they're old anyway. Force-overwrite them. :)

maybe future fickle will add support for multiple ghosts
from one replay for some sick memery but idgaf right now

Preview is fairly basic, and only shows players
rewinding. Full state is restored via reloading
the replay and jumping to the timestamp once
the rewind is done.