Open source changes for high density caching impl

- Serialization module improved to support multiple Data storage types
- Introduced Node & Client extensions (to support serialization abstractions)
- Improved partition service to support high density caching 
 
See https://github.com/hazelcast/hazelcast-enterprise/pull/66
Should this error not be propaged? Logging the exception is better than swallowing it, but if the logfiles are not checked,the effect is the same. Probably better to propagate it so that the caller 'knows' that the object isn't created successfully.