message: Add trigger selection
diff: -AliAnalysisTaskStrVsMult *AddTaskStrVsMult( )
  +AliAnalysisTaskStrVsMult *AddTaskStrVsMult(UInt_t triggerMask = AliVEvent::kINT7)
  {
  // analysis manager
  AliAnalysisManager *mgr = AliAnalysisManager::GetAnalysisManager();
  @@ -13,7 +13,7 @@ AliAnalysisTaskStrVsMult *AddTaskStrVsMult( )
  // Create the task and add it to the manager
  AliAnalysisTaskStrVsMult *mytask = new AliAnalysisTaskStrVsMult("StrVsMult_Task");
  - mytask->SetDefOnly(kTRUE);
  + mytask->SelectCollisionCandidates(triggerMask);
  mgr->AddTask(mytask);
  // output file name
  