Added tool selection for kerf width

CutToLength/Tool.cs

@@ -0,0 +1,14 @@
+namespace CutToLength
+{
+    public class Tool
+    {
+        public string Name { get; set; }
+        public double Kerf { get; set; }
+        public bool AllowUserToChange { get; set; }
+
+        public override string ToString()
+        {
+            return Name;
+        }
+    }
+}