Temporarily remove javolution serializer
Temporarily remove javolution serializer

Until [7.0.0 is released](https://github.com/javolution/javolution/issues/15), because
the 6.0.0 is broken.

Also remove the serializer-benchmark because it depends on the javolution
serializer.

mosoft521/memcached-session-manager,magro/memcached-session-manager,magro/memcached-session-manager,mosoft521/memcached-session-manager