message: Fixed bug: invalid file handles should be checked against -1, not 0
  Implemented DoesFileExist
  Implemented doesFolderExist
diff: @@ -322,7 +322,7 @@ namespace Utils
  {
  using namespace std;
  int inputHandle = open(sourcePath.c_str(), O_RDONLY);
  - if(inputHandle == 0)
  + if(inputHandle == -1)
  {
  LOG(LogLevel::Error) << "unable to open copy source path: " << sourcePath;
  return false;
  @@ -339,7 +339,7 @@ namespace Utils
  return false;
  }
  int outputHandle = open(destPath.c_str(), O_WRONLY | O_CREAT | O_TRUNC, inputStat.st_mode);
  - if(outputHandle == 0)
  + if(outputHandle == -1)
  {
  LOG(LogLevel::Error) << "unable to open copy destination file: " << destPath;
  close(inputHandle);
  @@ -381,14 +381,14 @@ namespace Utils
  bool DoesFileExist(const std::string& path)
  {
  - LOG(LogLevel::Error) << "DoesFileExist() has been stubbed out in LinuxUtils.cpp.";
  - exit(-1);
  + mode_t mode;
  + return GetFileMode(path, mode) && S_ISREG(mode);
  }
  bool doesFolderExist(const std::string& path)
  {
  - LOG(LogLevel::Error) << "doesFolderExist() has been stubbed out in LinuxUtils.cpp.";
  - exit(-1);
  + mode_t mode;
  + return GetFileMode(path, mode) && S_ISDIR(mode);
  }
  void WriteToConsole(LogLevel level, const std::string& logMessage)
  