Add 'bad-robot-ips' configuration file option

This is for robots making bad-robot requests that you want to block by
IP address instead of by user-agent and where you don't want to block
everything from the IP address or IP address range.
Allow configuration file directives to be continued across multiple lines

Lines are continued RFC822 style, by indented whitespace on the
continuation lines. This uses code taken from portnanny (qv)
because I already had it lying around.

I should have done this years ago.