client should handle all retry logic, batching of calls

[adobeDan]

In the helper, when doing a query, the paginate function handles server retries. But invoking a single action does not.

Similarly, the client should handle batching of calls for multiple users so as to reduce the chance of throttling errors and minimize overhead.

[adobeDan]

Turns out the client already handled the notion of a batch of calls. What it wasn't doing was automatically splitting large batches to handle server throttling. Making that a separate issue #16.