Add trap for SIGUSR1, to create report and terminate

Created by: ZaiLynch

I'm writing some code that interacts with Arachni. Unfortunately, my code is not able to send the appropriate input to make Arachni create a report and then terminate. I can send the SIGINT signal to cause the menu and I can also send the required letters ('r' / 'e'), by using something like

echo "e" > /proc/_ARACHNI_PID_/fd/0

though it's not registering the "Enter" signal afterwards, so Arachni doesn't react to the input.

I tried several other ways (printf, yes, ...) Eventually, I gave up and modified the Arachni source to add a new trap for USR1, that creates a report and then terminates Arachni. I would love to have this (or some other way to accomplish my goal) added to the official Arachni repo. My fork is located at https://github.com/Konsubuntu/arachni Could this be pulled?