SPRINGFIELD — Two years ago, the state’s top court urged lawmakers to craft more lenient rules for transferring juveniles to adult courts for serious crimes.And lawmakers responded, increasing the mandatory transfer age from 15 to 16 for crimes such as first-degree murder and aggravated sexual assault and giving judges the last word on when to transfer in many other cases.But lawyers are still looking for the last word on one aspect of the transfer issue — whether the changes apply retroactively.And the …