Client: add autofree option in client section (Feature #9 requested by lidstah (and tamtam)) See default wmfsrc

src/structs.h

@@ -396,6 +396,7 @@ typedef struct
           Bool place_at_mouse;
           Bool border_shadow;
           int borderheight;
+          char *autofree;
           uint bordernormal;
           uint borderfocus;
           uint resizecorner_normal;