Ubuntu Wily packages can also be used on Xenial and Yakkety. Centos 6 RPMs depend on libhiredis-0.12 now e.g. from https://pkgs.org/centos-6/puias-unsupported-x86_64/
Changes
- don't rollover session ids anymore and the keep same session cookie name over session updates
closes #204 (also don't remove sessions from cache before storing anymore)