* 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
* initial refactoring for the numRows param
* work on driver.NewBatchInsert
* work on NewBatchInsert
* batch insert seems to work
* switched testh.Insert to use BatchInsert
* doc cleanup
* batch insert for dbwriter and csv
* removed unneeded NumRows from driver.StmtExecer
* minor tidyup
