Revert "Merge pull request #350 from sjohnr/master"

This reverts commit ab8517e7d5b780980f516f82b01350052f9266e9, reversing
changes made to 6c8d4160c7901abaaea8cbcf29857994d305b7f5.
Ensure sockets are connected before we attempt to disconncet them.

Otherwise this test fails on OSX 10.9.4, zmq 4.0.3
Ensure that exception is thrown when polling invalid socket.
Merge pull request #353 from GreatFruitOmsk/master

Ensure that exception is thrown when polling invalid sockets.