Update tcos.cpp

add get Hostname function of linux 
#if defined(Q_OS_LINUX)
    QFile file("/etc/hostname");
      if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
          return ret;
    ret.append(file.readLine());
#endif
Merge pull request #52 from tsuibin/patch-1

Update tcos.cpp