Viewer of IsoFields is added

FieldVisualizer/Entities/Values/Primitives/ICenter.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace FieldVisualizer.Entities.Values.Primitives
+{
+    public interface ICenter
+    {
+        double CenterX { get;}
+        double CenterY { get;}
+    }
+}