Better signal handling for procutil

Check the various other types of termination and signal stats. Ignore
SIGSTOP/SIGCONT and handle abnormal termination by things like SIGABRT
and SIGSEGV and friends

Change-Id: I9bf48f1bc463aba41daac9cc55214bb550cf6f18
Reviewed-on: http://review.couchbase.org/28119
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>