[Box-Admins] Box3 updates

[Tobias Pape]

Dear Box team

in the process of trying to resurrect the Trunk CI job, 
I came across some maintenance tasks and took the liberty to 
take on them. Here's the relevant part of the admin-log:

20150330 tpape
Installed lsb-release for identification
Installed mc to browse .debs
Installed apt-file for maintenance operations and diagnosis

20150331 tpape
Installed xvfb for pseudo-headless Squeaks and for Jenkins graphics
Principled /etc/apt/sources.list to use mirror throughout
Installed debian-security-support as per https://wiki.debian.org/LTS/Using
Add /etc/apt/preferences.d/debian to ensure to prefer Debian packages should gandi do strange things
Updated all packages but jenkins; installed gnupg-curl as: 'gnupg recommends gnupg-curl'
Installed fontconfig (and defoma) so that jenkins can draw charts


Should you have comments or questions just go ahead :)

Best
	-Tobias