support for .NET framework 3.5

Still have bugs

Net35/HandyControl_Net35/Expression/Media/IGeometrySourceParameters.cs

@@ -0,0 +1,13 @@
+using System.Windows.Media;
+
+namespace HandyControl.Expression.Media
+{
+    public interface IGeometrySourceParameters
+    {
+        Stretch Stretch { get; }
+
+        Brush Stroke { get; }
+
+        double StrokeThickness { get; }
+    }
+}