Add polygon shape

StructureHelperCommon/Models/Shapes/IVertex.cs

@@ -0,0 +1,15 @@
+using StructureHelperCommon.Infrastructures.Interfaces;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StructureHelperCommon.Models.Shapes
+{
+    public interface IVertex : ISaveable
+    {
+        IPoint2D Point { get; set; }
+    }
+
+}