Fix LIBZMQ-576 - Revert "Merge pull request #76 from hintjens/master"

This reverts commit a0a24a92af78ebb8f61a8a45454d3ff6d2db0a3d, reversing
changes made to 8e748064acf877e5322f681c30323d7dc91e2100.

See https://zeromq.jira.com/browse/LIBZMQ-576 for details
Merge pull request #113 from vortechs2000/fix-libzmq-576

Fix LIBZMQ-576 - Revert "Merge pull request #76 from hintjens/master"
Adjust NEWS to include LIBZMQ-576
Merge pull request #114 from vortechs2000/fix_news

Adjust NEWS to include LIBZMQ-576
Merge pull request #115 from hintjens/master

Man page fixes
Fix a race (to crash) when a message is sent as the last connection is lost.

Active is reduced in the zmq internal thread in terminated, potentially to zero.
If the user thread is in send() between lines 109 and 116, then the old code "(current+1) % active" is a divide by 0 - and crashes the program.
Merge pull request #116 from daveab/master

Fix race to crash: when a message is sent as the last connection is lost

Fixes #1002
Updated NEWS