dist was skipping over pipes when one failed because the non-working pipe got
swapped with a working pipe but the write was never retried on that pipe

Fixed issue #325

Makefile.am wasn't fixed, so libzmq was not building

Mark sockets as invalid when closed, not reaped

Previously, sockets were still "valid" after being closed and only marked
as invalid when destroyed. This meant programs could access closed sockets.
Now the socket is marked "invalid" when closed.

Completed internal renaming of XREP/XREQ to ROUTER/DEALER

Fixed issue LIBZMQ-345 - race condition in ctx.socket/term allows segfault

Ctx patches

Fixed issue LIBZMQ-344 - Implementation of ZMQ_FAIL_UNROUTABLE is broken

* corrects whitespace errors
* fixes spelling errors in comments
* prefers #ifdef to #if defined

Fixed issue LIBZMQ-343 - zmq_msg_get/set are too complex

* Return integer property
* Fixed up man pages, which were inaccurate
* Fixed test case

Applied patch for issue #293 - zmq 2.1 doesn't follow the ZMTP/1.0 spec

remove unused variable

fix connection establishment for AF_UNIX sockets

Wrote new ctx API, added ZMQ_MAX_SOCKETS and ZMQ_IO_THREADS

Disable reconnection option

Add value -1 to the ZMQ_RECONNECT_IVL to disable the reconnection algorithm

Removed sys:// logging infrastructure

Removed last vestiges of thread-safe sockets

* Implemented new ctx API (_new, _destroy, _get, _set)
* Removed 'typesafe' macros from zmq.h
* Added support for MAX_SOCKETS (was tied into change for #337)
* Created new man pages

Fixed issue LIBZMQ-333 (zmq_devices is missing)

 - reverted commit 941be8d2.
 - fixed zmq_device implementation for latest socket_base class
 - added back zmq_device.3 man page