2.4.0

• Updates source image to 2.6.0.
• Updates CHANGELOG.md to simplify maintenance.
• Updates README.md to simplify contents and improve readability.
• Updates README-short.txt to apply to all image variants.
• Updates Dockerfile org.deathe.description metadata LABEL for consistency.
• Updates supervisord configuration to send error log output to stderr.
• Updates varnishd supervisord configuration file/priority to 80-varnishd-wrapper.conf/80.
• Updates varnishncsa supervisord configuration file/priority to 50-varnishncsa-wrapper.conf/50.
• Updates docker-compose example with redis session store replacing memcached for the apache-php service.
• Updates wrapper scripts timer to use UTC date timestamps.
• Updates backend probe window from 5 to 3 to reduce time to register an offline backend.
• Fixes docker host connection status check in Makefile.
• Fixes error when restarting/reloading varnishd.
• Adds inspect, reload and top Makefile targets.
• Adds improved clean Makefile target; includes exited containers and dangling images.
• Adds SYSTEM_TIMEZONE handling to Makefile, scmi, systemd unit and docker-compose templates.
• Adds system time zone validation to healthcheck.
• Adds lock/state file to wrapper scripts.
• Adds VCL to handle /status and /varnish-status for monitoring the backend and varnish respectively.
• Removes VARNISH_AUTOSTART_VARNISHD_WRAPPER, replaced with ENABLE_VARNISHD_WRAPPER.
• Removes VARNISH_AUTOSTART_VARNISHNCSA_WRAPPER, replaced with ENABLE_VARNISHNCSA_WRAPPER.
• Removes support for long image tags (i.e. centos-7-2.x.x).