FtpChdir - Change working directory on server.
       #include <ftplib.h>
       int FtpChdir(const char *path, netbuf *nControl);
       path   Specifies the desired working directory on the server.
       nControl
              A handle returned by FtpConnect().
       Sends  a  change  working  directory  request  to  the server using the
       specified path.
       Returns 1 if successful or 0 on error.