icons, libgimpwidgets: now with proper gimp-attach + gimp-detach icons.

"gimp-detach" does not just use "gtk-convert" anymore and has its own
design. As for "gimp-attach", this is not used anywhere (yet), but it
could be soon as reverse action of gimp-detach. For instance, this icon
can be used for bug 791859 when we implement re-attaching overlay
dialogs.

icons/icon-list.mk

@@ -61,6 +61,7 @@ scalable_images = \
 	scalable/gtk-yes.svg					\
 	\
 	scalable/gimp-anchor.svg				\
+	scalable/gimp-attach.svg				\
 	scalable/gimp-business-card.svg				\
 	scalable/gimp-cap-butt.svg				\
 	scalable/gimp-cap-round.svg				\
@@ -101,6 +102,7 @@ scalable_images = \
 	scalable/gimp-curve-smooth.svg				\
 	scalable/gimp-dashboard.svg				\
 	scalable/gimp-default-colors.svg			\
+	scalable/gimp-detach.svg				\
 	scalable/gimp-device-status.svg				\
 	scalable/gimp-display.svg				\
 	scalable/gimp-display-filter-clip-warning.svg		\
@@ -493,8 +495,10 @@ vector24_images = \
 	24/gimp-wilber.svg
 
 icons12_images = \
+	12/gimp-attach.png					\
 	12/gimp-close.png					\
 	12/gimp-default-colors.png				\
+	12/gimp-detach.png					\
 	12/gimp-linked.png					\
 	12/gimp-menu-left.png					\
 	12/gimp-menu-right.png					\
@@ -852,6 +856,7 @@ icons24_images = \
 	\
 	24/gtk-select-color.png					\
 	\
+	24/gimp-attach.png					\
 	24/gimp-business-card.png				\
 	24/gimp-center.png					\
 	24/gimp-channel-alpha.png				\
@@ -873,6 +878,7 @@ icons24_images = \
 	24/gimp-controller.png					\
 	24/gimp-cursor.png					\
 	24/gimp-dashboard.png					\
+	24/gimp-detach.png					\
 	24/gimp-device-status.png				\
 	24/gimp-display.png					\
 	24/gimp-display-filter-clip-warning.png			\

libgimpwidgets/gimpicons.h

@@ -33,7 +33,8 @@ G_BEGIN_DECLS
 
 /*  random actions that don't fit in any category  */
 
-#define GIMP_ICON_DETACH                    "gtk-convert"
+#define GIMP_ICON_ATTACH                    "gimp-attach"
+#define GIMP_ICON_DETACH                    "gimp-detach"
 #define GIMP_ICON_INVERT                    "gimp-invert"
 #define GIMP_ICON_RESET                     "gimp-reset"
 #define GIMP_ICON_SHRED                     "gimp-shred"