Clean up old APT pins that removed preferences
Disable apt-cacher-ng from wheezy-backports

Version of 'apt-cacher-ng' available via wheezy-backports at this point
in time has problems with package list expiration, so I'm disabling
installation ('apt-cacher-ng' from wheezy will be installed instead).

Problems with apt-cacher-ng using 99% CPU at random times could be fixed
temporarly by monit or some other means. No solution, however, is
presented at the moment.
Merge pull request #1 from drybjed/clean-up-apt-pins

Clean up APT pins
Regenerate README