close chatwindow if its associated contact is blocked/deleted

src/windows.h

@@ -225,6 +225,7 @@ void set_active_window(int ch);
 int get_num_active_windows(void);
 void kill_all_windows(void);    /* should only be called on shutdown */
 void on_window_resize(void);
+ToxWindow *get_window_ptr(int i);
 
 /* refresh inactive windows to prevent scrolling bugs. 
    call at least once per second */