app: add new action to restore a tool preset from the list

In order to make things more obvious here. Before, a tool preset could
only be rstored from the list by selecting it, which only worked if
another preset was active before. Now the selected preset can easily
be restored again.

app/actions/tool-presets-commands.h

@@ -0,0 +1,26 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __TOOL_PRESETS_COMMANDS_H__
+#define __TOOL_PRESETS_COMMANDS_H__
+
+
+void   tool_presets_restore_cmd_callback (GtkAction *action,
+                                          gpointer   data);
+
+
+#endif /* __TOOL_PRESETS_COMMANDS_H__ */