message: fixing el7 VS errors
  VS warnings 4250 and 4503
  BPSerializer::m_Mutex as protected is not valid in el7
  VS 2015 warning
diff: #include "BPSerializer.h"
  #include "BPSerializer.tcc"
  +#ifdef _WIN32
  +#pragma warning( \
  + disable : 4503) // Windows complains about MergeSerializeIndex long types
  +#endif
  +
  namespace adios2
  {
  namespace format
  