Decal runtimes

Created by: Skullyton

Point arrows don't disappear, Gibs are acting strangely

[06:17:07] Runtime in misc.dm, line 9: type mismatch: 0 += the arrow (/obj/effect/decal/point)

[05:53:49] Runtime in misc.dm, line 9: type mismatch: 0 += the gibs (/obj/effect/decal/cleanable/blood/gibs)