Also, this commit makes `ls` a per-item command.
A command that processes things item by item may still take some time to stream
out the results from a single item. For example, `ls` on a directory with a lot
of files could be interrupted in the middle of showing all of these files.
* start playing with ways to use the uniq command
* WIP
* Got uniq working, but still need to figure out args issue and add tests
* Add some tests for uniq
* fmt
* remove commented out code
* Add documentation and some additional tests showing uniq values and rows. Also removed args TODO
* add changes that didn't get committed
* whoops, I didn't save the docs correctly...
* fmt
* Add a test for uniq with nested json
* Add another test
* Fix unique-ness when json keys are out of order and make the test json more complicated
