* CSV now renames duplicate ingest headers
* Fix broken test
* xlsx ingester now handles duplicate col names
* Update CHANGELOG
* Additional tests for ingest.column.rename
* Removed dead comment in grammar
* implementation work for json importers
* json driver checkpoint
* working on json.ParseObjectsInArray
* json.ParseObjectsInArray seems to be working
* checkpoint while tidying up ParseObjectsInArray
* more tidy checkpoint
* more tidy checkpoint 2
* tidying up ParseObjectsInArray
* tidy up
* code/docs cleanup
* more cleanup of json driver
* more cleanup of json driver
* flat json import seemingly working
* improvements to json driver
* json writer now prints empty [] for postgres empty tables