Tweak ArdorIcon display-tool & re-order icons

* add option to render a border
* group icons (assume 7x7 grid)

libs/widgets/widgets/ardour_icon.h

@@ -29,28 +29,14 @@ namespace ArdourWidgets { namespace ArdourIcon {
 	enum Icon {
 		RecButton,
 		RecTapeMode,
-		CloseCross,
-		HideEye,
-		StripWidth,
-		DinMidi,
+		TransportPanic,
 		TransportStop,
 		TransportPlay,
 		TransportLoop,
 		TransportRange,
 		TransportStart,
 		TransportEnd,
-		TransportPanic,
 		TransportMetronom,
-		ScrollLeft,
-		ScrollRight,
-		NudgeLeft,
-		NudgeRight,
-		ZoomIn,
-		ZoomOut,
-		ZoomFull,
-		ZoomExpand,
-		TimeAxisShrink,
-		TimeAxisExpand,
 		ToolGrab,
 		ToolRange,
 		ToolCut,
@@ -58,6 +44,20 @@ namespace ArdourWidgets { namespace ArdourIcon {
 		ToolAudition,
 		ToolDraw,
 		ToolContent,
+		ZoomIn,
+		ZoomOut,
+		ZoomFull,
+		ZoomExpand,
+		TimeAxisShrink,
+		TimeAxisExpand,
+		StripWidth,
+		CloseCross,
+		HideEye,
+		ScrollLeft,
+		ScrollRight,
+		NudgeLeft,
+		NudgeRight,
+		DinMidi,
 		PsetAdd,
 		PsetSave,
 		PsetDelete,
@@ -65,11 +65,11 @@ namespace ArdourWidgets { namespace ArdourIcon {
 		PluginReset,
 		PluginBypass,
 		PluginPinout,
+		LatencyClock,
 		Config,
 		ConfigReset,
 		PowerOnOff,
-		LatencyClock,
-		NoIcon,
+		NoIcon //< Last
 	};
 
 	LIBWIDGETS_API bool render (cairo_t *cr,