Fixes for whatsnew. Thanks to maznaz!
Whatsnew: Show a TOC
3.1 does not yet work on Windows
Add Matt Wise to the contributors
Fixes batches after changes in master
Cosmetics for #1618: Does not need to_timestamp
Update tasks.rst

I believe the reference to the task that failed is a typo.  I might be wrong.
Now depends on billiard 3.3.0.2
Now depends on kombu 3.0.4
Cosmetics
AsynPool: -Ofair should not always schedule writes
Pool.flush may not exist
Log message "Skipping revoked tasks" is now "Discarding*" and is info instead of warn
Improve whatsnew
AsynPool: Make sure late terminated task is acked
Tests passing
Version 3.1.0
BROKER_FAILOVER_STRATEGY missing .. setting:: ref (Issue #1620)

The release tool complained::

<pre>
    ---> pavement.verifyconfigref
    PYTHONPATH=. /Users/asksol/.virtualenvs/def/bin/python extra/release/verify_config_reference.py             docs/configuration.rst
    Error: found undocumented settings:
    * BROKER_FAILOVER_STRATEGY
</pre>
Update CONTRIBUTORS.txt
Distribution cleanup and prepare for release