#5 Support nested properties

[ted stockwell]

Need to create properties for nested objects in an Entity.

For instance consider a 'Person' object with a nested address object...
Entity address= new Entity("Address");
address.setProperty("state", "IL");
Entity person= new Entiity("Person", "Ted");
person.setProperty("address", address);

For instance, to get persons that live in Illinois...
new Query("Person").where(eq("address/state", "IL"))

nested properties should be referenced in a query using '/'.

[ted stockwell]

NOTE: The Google Datastore API does not support nested Entities but I think that supporting nested Entities is simple and very useful