Removed -(no)push and -(no)forward flags from send, spost and whatnow.

Removed -(no)push and -(no)forward flags from send, spost and whatnow.
We don't send directly (with SMTP) anymore. We only execute sendmail,
which, on modern systems, takes few time. Thus we do it directly
instead of having more complexity for the rare wish to run sendmail in
the background and also be unable to deal with possible errors directly.