3824: Show stdout/stderr if shell cmd fails in install script.
3824: Use a docker volume for TASK_WORK, clean up env var and tmp dir handling, improve logging.
3824: Add dnsmasq to compute images, to make docker-in-docker work. refs #3333
3824: Do not say "There are  jobs in the queue ahead of this one" if queue_position is unknown.
3824: Use keep volumes big enough to store the arvados/jobs docker image. Do not clobber settings.conf if not starting apiserver.
3824: Fix up logging messages.
3824: Add sources.list file missing from commit:0f9aaf1
3824: Remove redundant addition of arvados package repo and key.
3824: Use Data::Dumper instead of custom quoting to show srun/task exec args.
3824: Merge branch 'master' into 3824-crunch-container-setup
3824: Bring back $! in error message, in case it's helpful.
3824: Set mode on /etc/fuse.conf in compute image.
3824: Remove redundant "apt-get update", standardize on "apt-get update -qq" and "apt-get install -qqy".
3824: Import GPG key needed for RVM installation.
3824: Fix comment to state that tasks must not assume $TASK_KEEPMOUNT is /keep.
3824: Merge branch 'master' into 3824-crunch-container-setup
Merge branch '3824-crunch-container-setup' closes #3824