A DynamoDB interface with JSON semantics

This module is meant to serve as a drop-in replacement to the standard simpljs database module, which uses a JSON-inspired API but is backed by a local indexedDB instance. This module uses the same semantics to work at cloud scale using Amazon DynamoDB as its backing store.

Neither DynamoDB nor this module currently support transactional operations as provided by indexedDB and the simpljs database module, so any necessary locking must be done at the application level.