Adds intraprocess communication so when the parent is sent a QUIT or a USR2 that it shuts down the child process. Inspired from https://github.com/stulentsev/resque-multi-job-forks/commit/502f97a3fd54dec09500d5c2110b9857ef428c25 , but changed the signal from TSTP to QUIT, because TSTP hard-kills the fork and is not trapped.