Warden 0.4.4

Enhancements:

• Updated php-fpm images to use fpm-loaders variant of base image to include IonCube & SourceGuardian from upstream images
• Updated php-fpm images fix for directory ownership of mounted volume paths for future flexibility by moving it to the docker-entrypoint script with an env var CHOWN_DIR_LIST to specify what directories to chown on container startup

Bug Fixes:

• Fixed missing SSH agent forwarding in php-blackfire container
• Fixed lack of extra_hosts in php-blackfire and blackfire-agent containers (issue #145)
• Fixed missing extra_hosts line for non-subdomain entry in /etc/hosts on selenium container
• Fixed $OSTYPE check for compatibility with OpenSUSE which uses linux rather than linux-gnu (#149 by @Den4ik)