Enables glob * to monitor all sub-groups.

Minimal script which gathers statistical data from /proc and /sys files
at specified interval. No data postprocessing is done, this script
gathers raw file content which will get parsed by other parts of
toolchain.

release v20210714

See merge request !54

http2() was part of dnssim since version 20210129 - and that is already
checked for.

plot-latency: ability to plot results as aggregated groups

See merge request !53

Each --group has user-supplied name, and line denoting average value,
and colored area denoting min/max range.

shotgun.output.dnssim

See merge request !52

- `reply/dnssim`: Fix luacheck warnings

- Move `dnssim` module from dnsjit's repository to shotgun's

cut-pcap.lua script to effectively trim already sorted PCAPs

See merge request !50

Intended use is together with merge_chunks.py like this:
merge_chunks.py ... | cut-pcap.lua - /tmp/short.pcap 60

Stock editcap is designed to handle unsorted PCAPs and thus cannot stop
on encountering first packet with timestamp over limit.
This is very ineffective for processing large PCAPs generated by
extract-clients.lua because the mergecap + editcap pipeline keeps
processing all the "trailing" data, which can take really large time for
no benefit.

add tool to plot packet rate in PCAPs

See merge request !46

merge_chunks: relax overly strict check on --seed

See merge request !48

shotgun: log total number of processed packets

See merge request !49

plot-response-rate: ability to plot sum of specified rcodes

See merge request !47

This allows to compare number of `discarded` with something meaningful.
It's much harder to pass this number to JSON but it is good enough as
stop-gap measure.

Funnily default value 0 was not accepted when specified explicitly.
https://docs.python.org/3/library/random.html says that full int
is acceptable so let's allow it.

configs: generate additional response-rate chart with non-zero rcodes

See merge request !44