quick edit to the fog color

Update to Ceno's skyline texture. Now uses parts of the REAL TRS alpha mask!

Also made it so Fairfield Terror uses the blue fog, my little blue building textures, and most importantly Ceno's skyline.

CHANGES:
Fixed something not a single person would notice but me.

CHANGES:

Fixed a mistake with No Mercy VMTS that caused the sky to appear incorrectly

CHANGES:

Dead Air now has its own skyline with colors that better fit the setting.
Fog color tuned to be a darker blue on No Mercy.
Made Ceno's skyline addon a dependency.