Allow more slack before calling a child process "Unresponsive"

Allow 120 seconds rather than 60 before calling a child process
"Unresponsive" -- there are quite a few monitored sites that take
around 60 seconds at times, and it was firing us too many alerts.
Add HTTP "Accept" header

Cloudflare was returning 403 if HTTP “Accept” header was not set. So I
set it now for text/html and text/plain. This is a good idea anyway.