*Add some distance check functions. By VladimirMangos.

--HG--
branch : trunk

src/game/GuardAI.cpp

@@ -126,7 +126,7 @@ void GuardAI::UpdateAI(const uint32 /*diff*/)
 
 bool GuardAI::IsVisible(Unit *pl) const
 {
-    return m_creature->GetDistance(pl) < sWorld.getConfig(CONFIG_SIGHT_GUARDER)
+    return m_creature->IsWithinDist(pl,sWorld.getConfig(CONFIG_SIGHT_GUARDER))
         && pl->isVisibleForOrDetect(m_creature,true);
 }