MarbleRunnerManager: create all runner tasks before launching them
MarbleRunnerManager: create all runner tasks before launching them

This should avoid hang in case a runner finishes and its address is
reused before the GUI thread has a chance to call the cleanup code.

probonopd/marble,utkuaydin/marble,Earthwings/marble,tzapzoor/marble,AndreiDuma/marble,rku/marble,Earthwings/marble,utkuaydin/marble,adraghici/marble,tzapzoor/marble,utkuaydin/marble,David-Gil/marble-dev,oberluz/marble,adraghici/marble,tzapzoor/marble,quannt24/marble,adraghici/marble,oberluz/marble,probonopd/marble,tzapzoor/marble,AndreiDuma/marble,tucnak/marble,Earthwings/marble,David-Gil/marble-dev,adraghici/marble,tucnak/marble,quannt24/marble,probonopd/marble,tzapzoor/marble,David-Gil/marble-dev,quannt24/marble,probonopd/marble,tucnak/marble,tucnak/marble,oberluz/marble,adraghici/marble,AndreiDuma/marble,AndreiDuma/marble,probonopd/marble,rku/marble,quannt24/marble,oberluz/marble,David-Gil/marble-dev,David-Gil/marble-dev,rku/marble,Earthwings/marble,oberluz/marble,utkuaydin/marble,rku/marble,quannt24/marble,AndreiDuma/marble,quannt24/marble,rku/marble,AndreiDuma/marble,Earthwings/marble,tzapzoor/marble,quannt24/marble,tucnak/marble,tzapzoor/marble,tucnak/marble,utkuaydin/marble,utkuaydin/marble,probonopd/marble,adraghici/marble,oberluz/marble,Earthwings/marble,tucnak/marble,David-Gil/marble-dev,tzapzoor/marble,rku/marble,probonopd/marble