move summary values into a struct

Rather than having { avg: 0.0, ... } in the json, it will now put
the summary values into an object like this:
{ summary: { avg: 0.0, ... } }
add `effio serve` to fire up webserver

also fix ignore
remove dead file
go fmt
remove finished TODO
add effio summarize-all

Finds all logs matching a filename pattern and creates summaries.

I could have done this with a small shell script but this was
pretty easy and keeps the ux simple.