check for available updates via apt-get on Debian and this Derivates.

Changelog: 2.9.0 21.09.2017 works with cmk version 1.4 2.8.1 23.01.2017 Fix mix kernel Packages Debian 7/8 thx to proximity.de 2.8.0 23.11.2016 Integration Agent Bakery 2.7.0 02.05.2016 activate Patch from dasmarci