message: wip string encoding fix (almost)
diff: #include "CesiumCreditSystem.h"
  +#include "UnrealConversions.h"
  #include "Cesium3DTiles/CreditSystem.h"
  #include <string>
  @@ -35,7 +36,7 @@ void ACesiumCreditSystem::Tick(float DeltaTime) {
  creditString += this->_pCreditSystem->getHtml(credit) + "\n";
  }
  creditString += "</body>";
  - Credits = creditString.c_str();
  + Credits = utf8_to_wstr(creditString);
  _pCreditSystem->startNextFrame();
  }
  