Bump version to 0.9.9
Run 'docker build' with '--rm' instead of '-rm', the latter which has been deprecated in Docker 0.9.
Upgrade to baseimage 0.9.9
Reintroduce Redis and memcached, but only in the passenger-customizable and passenger-full images
On Ruby 1.8, install Rake 10.1.1 because that's the last version supporting Ruby 1.8