message: Fix reference assignment
  Since m_ADIOS is a reference type then it can't be called with an explicit
  constructor
diff: @@ -20,7 +20,7 @@ Engine::Engine(ADIOS &adios, const std::string engineType,
  MPI_Comm mpiComm, const Method &method, const bool debugMode,
  const unsigned int nthreads, const std::string endMessage)
  : m_MPIComm{mpiComm}, m_EngineType{engineType}, m_Name{name},
  - m_AccessMode{accessMode}, m_Method{method}, m_ADIOS{adios},
  + m_AccessMode{accessMode}, m_Method{method}, m_ADIOS(adios),
  m_DebugMode{debugMode}, m_nThreads{nthreads}, m_EndMessage(endMessage)
  {
  if (m_DebugMode == true)
  