Log message:
comms: Replace RMD160 checksums with BLAKE2s checksums

All checksums have been double-checked against existing RMD160 and
SHA512 hashes

Log message:
comms: Remove SHA1 hashes for distfiles

Log message:
Import picocom-2.1 as comms/picocom.

As its name suggests, picocom is a minimal dumb-terminal emulation
program. It is, in principle, very much like minicom, only it's
"pico" instead of "mini"!

It was designed to serve as a simple, manual, modem configuration,
testing, and debugging tool. It has also served (quite well) as a
low-tech serial communications program to allow access to all types
of devices that provide serial consoles. It could also prove useful
in many other similar tasks.