Respawning Tweaks (#646)

changes:

rscadd: "Respawn timers are now tracked individually for playing as animals (mice), small synthetics (drones and pAIs) and crew (everything else). This means you can now play as a mouse or drone while waiting to respawn as a full crewmember.".
tweak: "You can now spawn as a drone immediately upon joining as an observer, without having to wait ten minutes. There is still a cooldown between respawning as a drone if you just died as one."
tweak: "Slightly improved the error messages if you try to respawn when you've not waited long enough."
In addition, unlisted changes:
The admin verb 'Allow player to respawn' now sets all three respawn timers
Respawn times are now centralised in setup #defines, for easier editing in future
Nonliving mobs will no longer attempt to ghost when deleted. A comment in mob.dm explains this change

code/modules/admin/verbs/randomverbs.dm

@@ -275,6 +275,19 @@ Ccomp's first proc.
 									   timeofdeath is used for bodies on autopsy but since we're messing with a ghost I'm pretty sure
 									   there won't be an autopsy.
 									*/
+	var/datum/preferences/P
+
+	if (G.client)
+		P = G.client.prefs
+	else if (G.ckey)
+		P = preferences_datums[G.ckey]
+	else
+		src << "Something went wrong, couldn't find the target's preferences datum"
+		return 0
+
+	for (var/entry in P.time_of_death)//Set all the prefs' times of death to a huge negative value so any respawn timers will be fine
+		P.time_of_death[entry] = -99999
+
 	G.has_enabled_antagHUD = 2
 	G.can_reenter_corpse = 1