Documentation and icons for FrameBuffer filters

unified icons, new entry in help window.

FrameBufferFilter.h

@@ -7,6 +7,17 @@
 class Visitor;
 class FrameBuffer;
 
+
+#define ICON_FILTER_DELAY 10, 15
+#define ICON_FILTER_RESAMPLE 1, 10
+#define ICON_FILTER_BLUR 0, 9
+#define ICON_FILTER_SHARPEN 2, 1
+#define ICON_FILTER_SMOOTH 14, 8
+#define ICON_FILTER_EDGE 16, 8
+#define ICON_FILTER_ALPHA 13, 4
+#define ICON_FILTER_IMAGE 1, 4
+
+
 class FrameBufferFilter
 {
     bool enabled_;