By Dan Marsh & S P Jones Neil Warnock has stepped down as Aberdeen’s interim manager, the club have announced. The news was confirmed in a statement shortly after Aberdeen’s 3-1 victory over Kilmarnock in the Scottish Cup quarter-finals. Chairman Dave Cormack revealed that the club’s search for a new long-term manager were “at an advanced stage”. He said: “The Club would like to thank both Neil and Ronnie Jepson for their efforts. With the search for a new manager at an advanced stage, Peter Leven will assume control of all first team matters until the process is concluded.” Warnock, 75, had o…