added target finding within box (thanks kjLotus!)

- added function to return position as Vector3 to Actor (todo: maybe we should just use the class instead of 3 separate floats?)
- added function to return all actors in Area
- actually added documentation to TargetFind stuff (kill me pls)
- todo: actually test this..

FFXIVClassic Common Class Lib/Vector3.cs

@@ -70,5 +70,41 @@ namespace FFXIVClassic.Common
         {
             return (lhs.X * rhs.X) + (lhs.Y * rhs.Y) + (lhs.Z * rhs.Z);
         }
+
+        public static float GetAngle(Vector3 lhs, Vector3 rhs)
+        {
+            var angle = (float)Math.Atan((rhs.Z - lhs.Z) / (rhs.X - lhs.X));
+            return lhs.X > rhs.X ? angle + (float)Math.PI : angle; 
+        }
+
+        public Vector3 NewHorizontalVector(float angle, float extents)
+        {
+            var newVec = new Vector3();
+            newVec.Y = this.Y;
+            newVec.X = this.X + (float)Math.Cos(angle) * extents;
+            newVec.Z = this.Z + (float)Math.Sin(angle) * extents;
+
+            return newVec;
+        }
+
+        public bool IsWithinCircle(Vector3 centre, float radius)
+        {
+            float diffX = centre.X - this.X;
+            float diffZ = centre.Z - this.Z;
+
+            float distance = (float)Math.Sqrt((diffX * diffX) + (diffZ * diffZ));
+
+            return distance < radius;
+        }
+
+        public bool IsWithinBox(Vector3 upperLeftCorner, Vector3 lowerRightCorner)
+        {
+            return upperLeftCorner.X <= this.X &&
+                upperLeftCorner.Y <= this.Y &&
+                upperLeftCorner.Z <= this.Z &&
+                lowerRightCorner.X >= this.X &&
+                lowerRightCorner.Y >= this.Y &&
+                lowerRightCorner.Z >= this.Z;
+        }
     }
 }