Merge pull request #55 from hintjens/master

Fixed issue #868
Fix timestamp counter on s390/s390x

Fixes #811
Only export zmq_* symbols
Merge pull request #56 from Debian/symbols

Only export zmq_* symbols
Merge pull request #57 from Debian/counter

Fix timestamp counter on s390/s390x
Backported fix for #888
Merge pull request #60 from ricnewton/master

Fix hang on terminate when inproc is connected but never bound
Updated NEWS
Updated for #60