BLE is now secured to require pairing with PIN

src/screen.h

@@ -5,4 +5,10 @@ void screen_print(const char * text);
 /// @return how many msecs can we sleep before we want service again
 uint32_t screen_loop();
 
-void screen_setup(), screen_on(), screen_off(), screen_press();
+void screen_setup(), screen_on(), screen_off(), screen_press();
+
+// Show the bluetooth PIN screen
+void screen_start_bluetooth(uint32_t pin); 
+
+// restore our regular frame list
+void screen_set_frames();