Predicate support for portable types

I have a requirement to support schema's that are realized at runtime. Hazelcast 3.0's portable serialization does allow me to provide distributed cache support for such data types, but the query/predicate support needed static pojo getter/setters. This PR addresses this.

I have added a PortablePredicateTest to illustrate the use case. 

Is this an acceptable approach? Please review and provide feedback, I will incorporate the review comments.

Thanks,
Varghese Cottagiri