message: added accelerator:backend parsing to xacc::getAccelerator()
diff: @@ -191,7 +191,13 @@ std::shared_ptr<Accelerator> getAccelerator(const std::string &name, std::shared
  error("XACC not initialized before use. Please execute "
  "xacc::Initialize() before using API.");
  }
  - auto acc = xacc::getService<Accelerator>(name);
  +
  + auto name_backend = split(name, ':');
  + auto acc = xacc::getService<Accelerator>(name_backend[0]);
  + if (name_backend.size() > 1) {
  + setOption(name_backend[0]+"-backend",name_backend[1]);
  + }
  +
  if (acc) {
  auto remoteacc = std::dynamic_pointer_cast<RemoteAccelerator>(acc);
  if (remoteacc) {
  @@ -210,7 +216,12 @@ std::shared_ptr<Accelerator> getAccelerator(const std::string &name) {
  error("XACC not initialized before use. Please execute "
  "xacc::Initialize() before using API.");
  }
  - auto acc = xacc::getService<Accelerator>(name);
  + auto name_backend = split(name, ':');
  + auto acc = xacc::getService<Accelerator>(name_backend[0]);
  + if (name_backend.size() > 1) {
  + setOption(name_backend[0]+"-backend",name_backend[1]);
  + }
  +
  if (acc) {
  acc->initialize();
  } else {
  