zsock_resolve return NULL if self is a socket descriptor
Add support for socket descriptors on windows.
events was not getting set on non WIN32 platforms.
zsock_resolve fd support on osx
zpoller fd support on osx
Unit test for fd support in zsock_resolve
Fix typo
zpoller fd support test
Merge branch 'master' into zpoller_fd_support
Merge branch 'msvc_build_fixes' into zpoller_fd_support
Cleanup according to CLASS
Update zsock_resolve docs
zpubsub implemented, with examples and doc
Added zpubsub_option class; using options in zpubsub.
Merge branch 'zpubsub'

Finished work on the zpubsub class, with corresponding zpubsub_option
static companion class.
Added check for broadcast interface in zpubsub_test, skipping system test
if no broadcast interface is available.
Merge pull request #670 from lovmoen/master

zpubsub class
Fix forcing into to bool warning.
Add missing exports to zgossip.
Make implicit casts explicit (fixes MSVC errors).