switch to sigaction and simple stack traces for illumos
more robust lua error messages for noit modules
fix lua 5.1 vs. 5.2 issue re: unpack
change some boot error message to debug messages
overhaul of the monitor to fix SIGSTOP race.

All signal based now using SIGALRM and SIGCHLD for timeouts
and noticing stopped children.  This removed the need to
detect out-of-band that a process is stopped making that
portable.  Add stack traces on other platforms.
Merge branch 'master' into MTEVerest