* maint:
  doc: Update zmq_socket(3) for 2.0.8 API changes
  Revert "Added man page for the zmq_device method"
  Revert "Added clean target that deletes generated man pages"
  Revert "Various changes to documentation project:"
  Revert "Reverting 'clean' change to Makefile"
  Revert "Removed empty man pages for old standalone devices"
  Revert "Further cleanups on reference manual"
  Revert "Small improvements to zmq_device(3) page"
  Revert "Removed wip zmq_deviced from master"