defined ColorBrush, added Interface as definition

Devices/Keyboard/ColorBrushes/IBrush.cs

@@ -0,0 +1,11 @@
+using System.Drawing.Color;
+using System.Drawing.Point;
+
+namespace CUE.NET.Devices.Keyboard.ColorBrushes
+
+{
+    public interface IBrush
+    {
+		public Color getColorAtPoint(Point point);
+    }
+}