Merge branch 'master', remote-tracking branch 'remotes/upstream/master'

* remotes/upstream/master:
  break up poller into separate processes
  add tooltip title to common_tabs
  PRIVACY: if wall is blocked, don't provide public keywords in HTML meta
  Diabook-dark update, it's almost useable now (if you're lenient).
  Added "important changes" to admin menu for admins who don't follow the github properly.

* master: