Merge branch 'master' into phpseclib

* master: (54 commits)
  updated geshi
  authpdo - use type safe comparison on passwords. fixes #1765
  removed unneeded files from random_compat
  Use cryptographically secure pseudo random number generator (CSPRNG)
  translation update
  translation update
  translation update
  translation update
  translation update
  or maybe I only now figured out the right travis config :-/
  disable 7.1 testing completely
  allow 7.1 failures until it's released #1682
  DE translation for key 'protected'
  Use 'Benachrichtigung' instead of 'Notifikation'
  Fix spelling of some terms (lower to upper case)
  DE translation for key: addUser_error_missing_pass
  DE translation for keys: update_name, update_mail
  translation update
  translation update
  Implemented interwiki substitution for external images (issue #1614).
  ...