task-guacamayo-devtools: added connman-tests package

Useful for setting up static IP config and such tasks that connman makes
hard to do, and documents completely wrongly.

For IPv4 config, use /usr/lib/connman/tests/set-ipv4-method; the service
name parameter is the name of the corresponding directory in /etc/connman
-- how's that for improving connman documenation by 100%?!
atom-pc: generate also tar.bz2 when creating images

Useful for updating installs on a real disk without having to use the live
image installer.