Update ioControl.cc

 Want to update Axis with the current toolnumber from the ATC ?
 Axis does not remember the current tool number, so once only detect from encoder / greyscale disc and the tool number becomes available to modified io module.
io triggers a toolchange state, instructing to change to the tool detected
Because that tool is already current, this component does nothing and passes back a 'toolchanged' signal
When io receives this it sets the appropriate NML code and axis updates the tool loaded display