Fix for Issue #17: allEntries on schemas with new lines (JSON-ified)

Integrated google-gson for more reliable serialization over the wire.
Added tests for JSON.
Client tests now submitted to persistence/multi-line tests.
I'm a bit wary of automagic POJO SerDe because it sometimes has unexpected results like including a bunch of fields (or worse, function returns) you don't actually need to send over the wire. For that reason, I like controlling serialization, and it's fairly straightforward anyway in this case...

That being said, I'll take a look.

Thanks for the links (: