function Owner (stat) {
  _define(this, 'read',
    function () {
      return Boolean(stat.mode & S_IRUSR);
    },
    function (v) {
      if (v) {
        stat.mode |= S_IRUSR;
      } else {
        stat.mode &= ~S_IRUSR;
      }
    }
  );
  _define(this, 'write',
    function () {
      return Boolean(stat.mode & S_IWUSR);
    },
    function (v) {
      if (v) {
        stat.mode |= S_IWUSR;
      } else {
        stat.mode &= ~S_IWUSR;
      }
    }
  );
  _define(this, 'execute',
    function () {
      return Boolean(stat.mode & S_IXUSR);
    },
    function (v) {
      if (v) {
        stat.mode |= S_IXUSR;
      } else {
        stat.mode &= ~S_IXUSR;
      }
    }
  );
}
Returns an octal representation of the `mode`, eg. "0754".

http://en.wikipedia.org/wiki/File_system_permissions#Numeric_notation

@return {String}
@api public