merge FreeTexture into FreeAndNilTexture

put back the old uteams cleanup, leaks and all, to worry about post-release since my attempt to use DeleteGear was running into the fact that that procedure does way more than just delete a gear. might need an explicit cleanup routine for both to call.

Fix in-flight colouring of land spray, make it use tint when added to land too (lua might find that handy), tweak climbhome cake delay slightly