[cvsnt] Latest updates

[Jerzy Kaczorowski]

> Borrow dialogs from TortoisePlink for ssh - not sure whether this'll
> stay as cvsnt is primarily a command line tool & bringing up dialogs
> isn't really its function...  Some sort of integration with wincvs
> could be managed here which would be better.

Well, I guess we can use our "stdenv" channel in cvsgui protocol. CVSNT
would only need to get the environmental variable of your choice in usual
manner, and WinCvs will display the dialog and return the input to CVSNT.

The only thing I need to know is the name of the variable. For reference
please see CVS_GETPASS variable which is used that way already.

As a side effect you get the ability to setup the thing to work from the
command line since it will also get the system environment setting as well.
So it will keep CVSNT as a command line tool and give the ability for GUI to
provide nice interface.

Ah, and let's not forget - Unix guys will probably be proud of you ;)

Best Regards,
Jerzy