EXCLUSIVE: After a series of creative differences between Deadpool director Tim Miller and star Ryan Reynolds, Miller has exited Deadpool 2. He hadn’t formally signed a deal to continue, but he was developing the script and by all accounts had planned to return behind the camera for a film Fox will release in 2018. I’ve confirmed from studio insiders this exit was over mutual creative differences, but this all ended amicably and the studio is very high on Miller and the…