message: "Bugfix": Rework C++14 std lib feature from MFEMSidreDataCollection
  Some of our users are using C++14, but pointing to an old standard library
  without a complete C++14 implementation.
  The emplace functions for ordered_maps with unique_ptrs produced compiler errors
  in the above configuration.
diff: @@ -2423,14 +2423,14 @@ void MFEMSidreDataCollection::reconstructFields()
  {
  // The vdim is being overwritten here with the value in the basis string so we
  // can correctly construct the QuadratureFunction
  - m_quadspaces.emplace(basis_name,
  + m_quadspaces[basis_name] = std::unique_ptr<mfem::QuadratureSpace>(
  detail::NewQuadratureSpace(basis_name, mesh, vdim));
  is_gridfunc = false;
  }
  // Only need to create a new FEColl if one doesn't already exist
  else if(m_fecolls.count(basis_name) == 0)
  {
  - m_fecolls.emplace(basis_name,
  + m_fecolls[basis_name] = std::unique_ptr<mfem::FiniteElementCollection>(
  mfem::FiniteElementCollection::New(basis_name.c_str()));
  }
  @@ -2466,8 +2466,7 @@ void MFEMSidreDataCollection::reconstructFields()
  auto parmesh = dynamic_cast<mfem::ParMesh*>(mesh);
  if(parmesh)
  {
  - m_fespaces.emplace(
  - basis_name,
  + m_fespaces[basis_name] = std::unique_ptr<mfem::ParFiniteElementSpace>(
  new mfem::ParFiniteElementSpace(parmesh,
  m_fecolls.at(basis_name).get(),
  vdim,
  @@ -2476,8 +2475,7 @@ void MFEMSidreDataCollection::reconstructFields()
  else
  #endif
  {
  - m_fespaces.emplace(
  - basis_name,
  + m_fespaces[basis_name] = std::unique_ptr<mfem::FiniteElementSpace>(
  new mfem::FiniteElementSpace(mesh,
  m_fecolls.at(basis_name).get(),
  vdim,
  