app: avoid duplicate offset actions

Blacklist the "tools-offset" action in the GUI, and only keep
"filters-offset", to avoid duplication.  Update gimp:offset's
description, so that "filters-offset" gets a proper tool-tip.

(cherry picked from commit 42d4255262)

app/operations/gimpoperationoffset.c

@@ -33,6 +33,8 @@
 
 #include "gimpoperationoffset.h"
 
+#include "gimp-intl.h"
+
 
 enum
 {
@@ -112,8 +114,8 @@ gimp_operation_offset_class_init (GimpOperationOffsetClass *klass)
 
   gegl_operation_class_set_keys (operation_class,
                                  "name",        "gimp:offset",
-                                 "categories",  "gimp",
+                                 "categories",  "transform",
-                                 "description", "GIMP Offset operation",
+                                 "description", _("Shift the pixels, optionally wrapping them at the borders"),
                                  NULL);
 
   g_object_class_install_property (object_class, PROP_CONTEXT,

app/widgets/gimpaction.c

@@ -334,6 +334,7 @@ gimp_action_is_gui_blacklisted (const gchar *action_name)
       "tools-brightness-contrast",
       "tools-curves",
       "tools-levels",
+      "tools-offset",
       "tools-threshold"
     };
 

po/POTFILES.in

@@ -297,6 +297,7 @@ app/operations/gimpoperationcurves.c
 app/operations/gimpoperationdesaturate.c
 app/operations/gimpoperationhuesaturation.c
 app/operations/gimpoperationlevels.c
+app/operations/gimpoperationoffset.c
 app/operations/gimpoperationposterize.c
 app/operations/gimpoperationsemiflatten.c
 app/operations/gimpoperationthreshold.c