since this is denied, I post this with tweaking the base idea.
still, there should be a way that a mob can see something regardless of their sight flags.
new type "/blackmatter"
its parent_type is "/atom/movable"
every mob is considered to have 'SEE_BLMATTER' at their sight flag which means they can always see blackmatter types.
Case A:
* You can't see things behind a wall
* the game has "/blackmatter/silhouette"
* a mob behind the wall has "/blackmatter/silhouette"
* Even if loc is hidden, you can see their silhouette
Case B:
* there's a turf that you can't see
* the turf has "/blackmatter/luminosity"
* You can see luminosity effects from the location even if the turf is not visible.
