Fix copy+paste of PegCurveGenerator always producing BrickCurveGenerator

src/IntelOrca.PeggleEdit.Tools/Levels/Children/BrickCurveGenerator.cs

@@ -11,6 +11,13 @@ public class BrickCurveGenerator : CurveGenerator
 
         public override int Type => LevelEntryTypes.BrickCurveGenerator;
 
+        public override object Clone()
+        {
+            var copy = new BrickCurveGenerator(Level);
+            base.CloneTo(copy);
+            return copy;
+        }
+
         public BrickCurveGenerator(Level level)
             : base(level)
         {

src/IntelOrca.PeggleEdit.Tools/Levels/Children/CurveGenerator.cs

@@ -177,12 +177,10 @@ private PointF GetVisualLocation(PointF location)
             return location;
         }
 
-        public override object Clone()
+        protected void CloneTo(CurveGenerator copy)
         {
-            var copy = new BrickCurveGenerator(Level);
             base.CloneTo(copy);
             copy.BezierPath = BezierPath.Clone();
-            return copy;
         }
 
         public void RecalculateOrigin()

src/IntelOrca.PeggleEdit.Tools/Levels/Children/PegCurveGenerator.cs

@@ -16,6 +16,13 @@ public PegCurveGenerator(Level level)
 
         public override int Type => LevelEntryTypes.PegCurveGenerator;
 
+        public override object Clone()
+        {
+            var copy = new PegCurveGenerator(Level);
+            base.CloneTo(copy);
+            return copy;
+        }
+
         public override void InvalidatePath()
         {
             _cache.Clear();