* Moved `source.Files` to its own package, thus the type is now `files.Files`.
* Moved much of the location functionality from pkg `source` to its own package `location`.
* Type Detector refactor
* json driver impl; refactoring of source.Files reader et al
* working on kind detector
* significant switcheroo of packages
* partway throught refactoring Kind
* major package switcheroo for Kind
* 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
