Add incoming answer to call control, also allow to send recall tone

src/test/dummy.c

@@ -2,6 +2,7 @@ void call_rx_audio() { }
 void call_out_setup() { }
 void call_out_release() { }
 void call_out_disconnect() { }
+void call_out_answer() { }
 void print_help() { }
 void sender_send() { }
 void sender_receive() { }