* go1.21: changes to support slog as part of stdlib
* Removed accidentially checked-in line of code
* Fixed minor linting issues; reenable typecheck
* go1.21: switched to stdlib slices pkg
* 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