Fixed AABB GetCenter to use Min.Y

AABB.cs

@@ -158,7 +158,7 @@ namespace Voxel
         {
             return new Vector3(
                 (Min.X + Max.X) / 2,
-                (Min.Y + Max.Y) / 2,
+                Min.Y,
                 (Min.Z + Max.Z) / 2
             );
         }

Entity.cs

@@ -105,7 +105,7 @@ namespace Voxel
 
             OnGround = moveVector.Y != originalVector.Y && originalVector.Y < 0;
 
-            Position = new Vector3(body.GetCenter().X, body.Min.Y, body.GetCenter().Z);
+            Position = body.GetCenter();
         }
 
         public void ApplyImpulse(Vector3 force)