outstanding telnetd bug fix, and two new features

[Cathey, Jim]

>Patch deletes this [FIXME] comment
>without ever explaining why, or including
>a fix. Do we handle sending of 0xff, or not?
>If not, why do you delete the comment?

The patch deletes the FIXME comment, because the patch
fixes the problem!  The escape character for IAC is IAC,
hence the IAC-IAC being turned into a single literal 0xFF.
The first string of '-' markers in the patch file deletes
the comment, the first string of '+' markers fixes the bug.

>I do not understand why this mode prevents you
>from not breaking code style. But anyway,
>I fixed discrepancies in style while applying
>parts of the patch.

The patch had a trailing else that led into an if
chain that formally should have been braced as a
single clause, for clarity.  Or else had the else
and the if sucked together as an "else if", as
used elsewhere.

>Applied, thanks. [SO_KEEPALIVE] I do not think we need
>the option to turn it off, and it's smaller that way.

Dealer's choice!  I was uncomfortable just turning it
on without the associated -n flag just in case.

-- Jim