* 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`.
* 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
* Moved time functions from pkg stringz to pkg timez
* Refactor options.Opt
* wip: initial work on configurable time layout
* wip: most printers now respect format.datetime and friends
* Folded pkg timefmt into timez
* Refactor options.Opt; refine options
* Add 'sq config set OPTION --help' mechanism
* Finished completion of OptDateFormatAsNumber and OptTimeFormatAsNumber
