socket.endpoint() returns empty string
Merge pull request #28 from rodgert/master

fix #27 thread tests hang on Ubuntu
Deadlock in socket.cancel() because of recursive lock of non-recursive mutex
test_socket_monitor refactored to don't have cyclic owning. Also more assertions added
Merge pull request #29 from oliora/master

Bug fixes
Make socket extension mechanism private detail

See discussion of https://github.com/zeromq/azmq/pull/12
Merge remote-tracking branch 'upstream/master'

Conflicts:
	azmq/detail/socket_service.hpp