Removing old, unreferenced file.

Painting/SvgGradientUnit.cs

-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace Svg
-{
-    /// <summary>
-    /// Defines the various cordinate systems that a gradient server may use.
-    /// </summary>
-    public enum SvgGradientUnit
-    {
-        /// <summary>
-        /// Indicates that the coordinate system of the entire document is to be used.
-        /// </summary>
-        UserSpaceOnUse,
-        /// <summary>
-        /// Indicates that the coordinate system of the element using the gradient is to be used.
-        /// </summary>
-        ObjectBoundingBox
-    }
-}