~mvo/update-manager/not-automatic

* AutoUpgradeTester/*
  - moved the upgrade tester code to its own directory
* AutoUpgradeTester/profile/*:
  - fixes for the new location
* AutoUpgradeTester/profile/etch-server/:
  - added etch upgrade test (not work yet)
* AutoUpgradeTester/automatic-upgrade-testing:
  - return proper exit status
* DistUpgrade/DistUpgradeCache.py:
  - log if DistUpgradeCache.markInstall() fails
  - added checkPriority() that will ensure that the configured
    priority is always present on upgrade (currently set to 'required')
  - added Distro/AllowUnauthenticated option
* DistUpgrade/DistUpgradeControler.py:
  - if on rewriting the sources.list everything fails (no mirror,
    enabling via aptsources) fallback to just overwriting it
  - do not crash if a BaseDependency can not be found in the cache
  - error out if backports can not be found (pre-requists)
  - copy main.log to main_pre_req.log before restarting itself
* DistUpgrade/DistUpgradeViewNonInteractive.py:
  - fix automatic re-runing of broken maintainer scripts