implement zwlr_foreign_toplevel_management protocol (#452)

* implement zwlr_foreign_toplevel_management protocol

* check if initial id is empty

src/ifs/wl_seat.rs

@@ -474,7 +474,7 @@ impl WlSeatGlobal {
 
     pub fn set_fullscreen(&self, fullscreen: bool) {
         if let Some(tl) = self.keyboard_node.get().node_toplevel() {
-            tl.tl_set_fullscreen(fullscreen);
+            tl.tl_set_fullscreen(fullscreen, None);
         }
     }