Syncing more then 999 elements does not work

[bmihelac]

When syncing more then 1000 items, Chrome just stopped doing it.

It seems there is an restriction for in clause to have at most 999
elements.

I have make workaround that seems to work in branch:

https://github.com/bmihelac/persistencejs/tree/batch-sync

Quick tests shows that it works, but I wouldnt merge it until properly tested.

[MarkMYoung]

Good work, Bojan. I had to do something similar a few months ago (except mine was asynchronously recursive), but I couldn't get permission to give it back to Zef until now.

I added synchronization tiers to prevent children from being sent to the server before the parent was committed. I also added a function to make complex read-only queries without Entities to make use of Zef's abstraction of browser result sets.