[rt-devel] overhauling the $MailCommand bit

[seph]

The config varibles $MailCommand, $SendmailArguments, and
$SendmailPath frequently confuse users. I was going to suggest
re-naming them, but I'm not sure what to rename them too, and after
staring at the code I think it needs to be tweaked a bit. 

I'm not yet sure how. Has anyone thought much about this? When I
figure out how I think it should work, I'll send a patch, but I
haven't figured that out yet.

seph