TBEvent: Fix cppheck warnings.

TBEvent: Fix cppheck warnings.

Pass strings by const reference, not by value.

TestBeam/TBEvent/TBEvent/TBTailCatcher.h

 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef TBEVENT_TBTAILCATCHER_H
@@ -57,7 +57,7 @@ class TBTailCatcher : public TBBeamDetector,
   /////////////////
 
   const std::vector<signal_type>& getSignals() const;
-  signal_type getSignal(std::string thisScintName) const;
+  signal_type getSignal(const std::string& thisScintName) const;
   signal_type getSignal(const TBScintillator* thisScint) const;
   
  private:

TestBeam/TBEvent/TBEvent/TBTailCatcherRaw.h

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
 */
 
 #ifndef TBEVENT_TBTAILCATCHERRAW_H
@@ -57,7 +57,7 @@ class TBTailCatcherRaw : public TBBeamDetector,
   /////////////////
 
   const std::vector<signal_type>& getSignals() const;
-  signal_type getSignal(std::string thisScintName) const;
+  signal_type getSignal(const std::string& thisScintName) const;
   signal_type getSignal(const TBScintillatorRaw* thisScint) const;
   
  private:

TestBeam/TBEvent/src/TBTailCatcher.cxx

 /*
-  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
 */
 
 
@@ -61,7 +61,7 @@ const std::vector<double>& TBTailCatcher::getSignals() const
 }
 
 double
-TBTailCatcher::getSignal(std::string thisScintName) const
+TBTailCatcher::getSignal(const std::string& thisScintName) const
 {
   return ( this->findIndex(thisScintName) < m_signals.size() )
     ? m_signals[this->findIndex(thisScintName)]

TestBeam/TBEvent/src/TBTailCatcherRaw.cxx

 /*
-  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
 */
 
 
@@ -60,7 +60,7 @@ const std::vector<int>& TBTailCatcherRaw::getSignals() const
 }
 
 int
-TBTailCatcherRaw::getSignal(std::string thisScintName) const
+TBTailCatcherRaw::getSignal(const std::string& thisScintName) const
 {
   return ( this->findIndex(thisScintName) < m_signals.size() )
     ? m_signals[this->findIndex(thisScintName)]