more s/test/command/g

Cleaned up some strings still referring to commands as tests.
rename test.json to command.json
update comment
rework inventory route on effio -serve
write summary files out with sha1 filenames

The filenames were useless anyways. Next commit will have full
command data in the summaries so it's all together making filenames
irrelevant (as they should be).

The SHA1 checksum is generated from the source CSV file, not the
summary data, so regenerating from the same source will overwrite
the same output file.
Clean up fio --output=json input/output.

This was the oldest code in this repo and came over from
a different project so it was very out of data.

Merged types.go into fio_output_json.go since none of those
types are used elsewhere.

Changed ClientStats to Jobs to match fio.  I have no idea where
the client_stats thing came from.
use MaxTs/MinTs like the rest of effio
go fmt
append output.json and command.json to summary data

Also updated timestamp names to match others.

Depends on 218736a5f37c7c47df46c5a852747875b84bdac7