Add a possibility to set a custom InstantiationStrategy. The Kryo.DefaultInstantiatorStrategy implements the usual Kryo behavior, where it tries to invoke a no-arg constructor when it needs to create a new instance.
But when org.objenesis.strategy.StdInstantiatorStrategy is used, then new instances are created without invoking a no-arg constructor, even if such a constructor is available. This improves Kryo's performance on fast-serialization tests (see issue #138)