Right click on the "add layer" button creates a new layer with a copy of the current layer contents

Suggested by ilkke.


git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@2092 416bcca6-2ee7-4201-b75f-2eb2f807beb1

src/layers.h

@@ -21,6 +21,7 @@
 */
 
 void Button_Layer_add(void);
+void Button_Layer_duplicate(void);
 void Button_Layer_remove(void);
 void Button_Layer_menu(void);
 void Button_Layer_set_transparent(void);