Add a colored overlay to Meson-vision

[mozi]

Mesons used to show the every turf at the actual light level (and work as a decent way to see that somebody was behind a wall). Until some code update fucked it up.

Should just be fixed instead of patching it with some overlay.

Fullbright's nice though cause damaged areas have their lights blown out and are dark. Also before fullbright you could see people moving around out of sight if they had flashlights on.