Allow JSON format to be an array (vs. an object) to support full DB exports

Right now you can only export a single query at a time. It'd be fabulous to put several of these together into a single DB export JSON as a simple JSON array of these export objects.

It could be something similar to CouchDB's bulk docs format:
{"exports":[{"query"....},{"query"....}]}

or just an array
[{"query"....},{"query"....}]
