``/mob/dead/observer`` -> ``/mob/observer/dead``
``/mob/eye`` -> ``/mob/observer/eye``
Reason being that they are similar in that they both don't interact with
the world in any way. Some procs were shared, some checks as well, and
it overall makes more sense this way. Plus, there were no ``/mob/dead``
mobs.
The wizard den is no longer pitch black.
Fixes targeted spells using the wrong caster/source.
Adds some missing checks using the caster source above.
Re-logging should no longer cause a loss of spell UI icons.
Mind transfer should no longer cause unintended spell loss.
