Mousetrap, mouse and spawning fixes (#1497)

Adjusts mousetraps a bit. So they'll be triggered by all mobs instead of only humans, and trigger when walked on. Also nerfs the instastun that comes from stepping on them without shoes, because that's pretty broken against giant monsters like vaurca breeders. applies halloss instead based on mob size. Smaller things get hurt more.

Fixes #1445 
Fixes #1449 
Fixes #1450

code/modules/ghosttrap/trap.dm

@@ -21,7 +21,7 @@ var/list/ghost_traps
 
 /datum/ghosttrap
 	var/object = "positronic brain"
-	var/minutes_since_death = 0     // If non-zero the ghost must have been dead for this many minutes to be allowed to spawn
+	var/respawn_check = 0//Which respawning test we check against
 	var/list/ban_checks = list("AI","Cyborg")
 	var/pref_check = BE_SYNTH
 	var/ghost_trap_message = "They are occupying a positronic brain now."
@@ -37,7 +37,7 @@ var/list/ghost_traps
 
 // Check for bans, proper atom types, etc.
 /datum/ghosttrap/proc/assess_candidate(var/mob/dead/observer/candidate, var/mob/target)
-	if(!candidate.MayRespawn(1, minutes_since_death))
+	if(!candidate.MayRespawn(1, respawn_check))
 		return 0
 	if(islist(ban_checks))
 		for(var/bantype in ban_checks)
@@ -174,7 +174,7 @@ var/list/ghost_traps
 	list_as_special_role = FALSE
 
 /datum/ghosttrap/drone/New()
-	minutes_since_death = DRONE_SPAWN_DELAY
+	respawn_check = MINISYNTH
 	..()
 
 datum/ghosttrap/drone/assess_candidate(var/mob/dead/observer/candidate, var/mob/target)