Implemented NPC special ability 40 'NPC_CHASE_DISTANCE'

Param 0: Sets max distance you need to be away from an npc for it to chase you.
Param 1: Sets min distance you need to be from npc for it to chase you.
Usage: Ideally used with ranged attack npcs / casters who you DO NOT WANT
to chase you unless you get too close or too far or out of sight.

zone/mob.cpp

@@ -183,6 +183,7 @@ Mob::Mob(const char* in_name,
 	has_MGB = false;
 	has_ProjectIllusion = false;
 	SpellPowerDistanceMod = 0;
+	last_los_check = false;
 
 	if(in_aa_title>0)
 		aa_title	= in_aa_title;
@@ -341,6 +342,7 @@ Mob::Mob(const char* in_name,
 		viral_spells[i] = 0;
 	}
 	pStandingPetOrder = SPO_Follow;
+	pseudo_rooted = false;
 
 	see_invis = in_see_invis;
 	see_invis_undead = in_see_invis_undead != 0;