Fixes to experimental transports in docs
Fix _set_task_join_will_block to actually use argument.
My fix for issue  #1722: unix sockets not working when redis configured as a backend
protov2: shadow field
Now depends on billiard 3.3.0.12
Cosmetics for #1724
Merge branch 'dsign/master'
Remove unused default_params (Issue #1724)
Python 3 fix for slots. Closes #1721
Merge pull request #1719 from ionelmc/patch-1

Fix _set_task_join_will_block to actually use argument.
Update CONTRIBUTORS.txt
Merge pull request #1726 from ionelmc/patch-2

Update CONTRIBUTORS.txt
Do not apply eventlet/gevent patches to celery multi.  Closes #1717
Must keep maxtasks * 4 events in heap
Tests passing
events.State now supports callbacks for on_node_join/on_node_leave, also fixes #1728
Chord join must use with allow_join_result()
Fixes Redis backend
Chord unlock must be called after header.  Closes #1700
unlock_chord task should raise Retry