Allow stdin/stdout redirection for the CLI conf (not mconf).
This allows to recall a sample and automatically apply the defaults
to new configuration option, with something like the following:
yes "" |ct-ng "sample_name"
1 This is NOT the official version of dialog. This version has been
2 significantly modified from the original. It is for use by the Linux
3 kernel configuration script. Please do not bother Savio Lam with