Merge pull request #1083 from hurtonm/master

Code cleanup
Fix failed assertion for WSAENOTSOCK

In de9eef306, the error number assigned to WSAENOTSOCK was EFAULT, but
zmq.cpp:919 expects an ENOTSOCK in this case.
Merge pull request #1088 from olafmandel/WSAENOTSOCK

Fix failed assertion for WSAENOTSOCK
program dumps core when getpeername() returns EINVAL (#1085)
Merge pull request #1089 from jkryl/master

program dumps core when getpeername() returns EINVAL (#1085)
Code cleanup