- implemented IOCTL_SERIAL_WAIT_ON_MASK for DeviceIoControl
  on serial lines in ntdll
- now using thread pool (instead of simple thread) for the
  background operations (this should help some high load
  situations)
- used this to implement WaitCommEvent on top NtDll functions
- in kernel32, removed now the no longer used termios/ioctls...
  for comm devices