Automatic healing and other medical stuff

- A mob with health > 0 will now slowly heal, around 1 damage per minute, unless it's cloneloss. This can be accelerated by sleeping.
- A mob with health < 0 will now slowly be damaged, also around 1 damage per minute. This can be decellerated by sleeping.
- Movement is no longer slowed by damage(unless it's a broken/missing bone), but only by trauma. This means that painkillers will help with movement speed.
- Painkillers now remove the red flashes and pain messages.

code/modules/mob/living/carbon/human/human.dm

@@ -168,7 +168,7 @@
 
 	if (istype(loc, /turf/space)) return -1 // It's hard to be slowed down in space by... anything
 
-	var/health_deficiency = (100 - health)
+	var/health_deficiency = traumatic_shock
 	if(health_deficiency >= 40) tally += (health_deficiency / 25)
 
 	var/hungry = (500 - nutrition)/5 // So overeat would be 100 and default level would be 80

code/modules/mob/living/carbon/human/life.dm

@@ -8,6 +8,8 @@
 
 		temperature_alert = 0
 
+		// used to do some stuff only on every X life tick
+		life_tick = 0
 
 /mob/living/carbon/human/Life()
 	set invisibility = 0
@@ -19,6 +21,8 @@
 	if(!loc)			// Fixing a null error that occurs when the mob isn't found in the world -- TLE
 		return
 
+	life_tick++
+
 	var/datum/gas_mixture/environment = loc.return_air()
 
 	// clean all symptoms, they must be set again in this cycle
@@ -75,6 +79,9 @@
 
 	handle_pain()
 
+	// Some mobs heal slowly, others die slowly
+	handle_health_updates()
+
 	// Update clothing
 	update_clothing()
 
@@ -103,6 +110,23 @@
 
 /mob/living/carbon/human
 	proc
+		handle_health_updates()
+			// if the mob has enough health, she should slowly heal
+			if(health >= 0)
+				var/pr = 5
+				if(stat == 1) // sleeping means faster healing
+					pr += 3
+				if(prob(pr))
+					heal_organ_damage(1,1)
+					adjustToxLoss(-1)
+			else if(health < 0)
+				var/pr = 8
+				// sleeping means slower damage
+				if(stat == 1)
+					pr = 3
+				if(prob(pr))
+					adjustToxLoss(1)
+
 		clamp_values()
 
 			SetStunned(min(stunned, 20))

code/modules/mob/organ/pain.dm

@@ -34,6 +34,10 @@ mob/proc/pain(var/partname, var/amount, var/force)
 mob/living/carbon/human/proc/handle_pain()
 	// not when sleeping
 	if(stat >= 2) return
+	if(reagents.has_reagent("tramadol"))
+		return
+	if(reagents.has_reagent("oxycodone"))
+		return
 	var/maxdam = 0
 	var/datum/organ/external/damaged_organ = null
 	for(var/name in organs)