NoMachine did not finish coding child process ending detection logic.
Added the needed code so that child process handle is added to the
handles that WaitForMultipleObjects() waits for in nomachine select()
implementation in socket.c. Otherwise select() would be stuck in
read/write dectection even when the process of interest has exited.
sftp-server.exe code modified to work in Windows as NoMachine never
finished it to work. I/O handling to work as a subsystem and
openssh7.1p1 sshbuf_new() buffer system code had to be used. sshd_config
file need location of sftp subsystem to be specified.
ssh.exe client invoked underneath was not able to send password prompt
and read password from user as stdin and stdout handles were redirected
to sockets by sftp.exe ; stderr which is not redirected is used to show
prompt to users and data is read from console
