Add disconnect and unbind documentation

Fix #366 - On Windows, preventing sockets to be inherited by child processes.

Simplify encoder's loop

Fix issue #268

This patch fixes a bug in the message encoder which was
responsible for computing incorrect message offset.
The bug affected PGM receiver making it unable to
decode inital messages.

Fix for issue 355 and fix for compile error with Visual C++ 2008

File decoder.cpp does not compile with Visual C++ 2008:

1>c:\tmp\libzmq\src\decoder.cpp(117) : warning C4003: not enough actual parameters for macro 'max'
1>c:\tmp\libzmq\src\decoder.cpp(117) : error C2589: '(' : illegal token on right side of '::'
1>c:\tmp\libzmq\src\decoder.cpp(117) : error C2059: syntax error : '::'
1>c:\tmp\libzmq\src\decoder.cpp(117) : error C2143: syntax error : missing ';' before '{'

This error is caused by the precense of a macro 'max' when including
'windows.h'. To solve this problem, the preprocessor macro /DNOMINMAX must
be specified.

Fix for issue 355. Added missing source files dealer.cpp, device,cpp and router.cpp. Removed source files no longer present: xrep.cpp and xreq.cpp

Async connect error handling

Patch from Mato that fixes a subtle connect bug: EAGAIN was being used as a translation value for EINPROGRESS, thus
shadowing a real EAGAIN return value from the OS.  This caused later
assertions of "Invalid argument" in stream_engine.cpp when it attempted to
use a socket which was not connected.

I also add EINTR to mean EINPROGRESS, as per the POSIX and FreeBSD
documentation which specifies that a connect() call interrupted due to a
signal will complete asynchronously.
Signed-off-by: Martin Lucina <martin@lucina.net>

Fix decoder to properly handle large messages

Fix issue #264

socket_base: process_unplug () is not used, remove it

Do not crash when multiple peers connect to PAIR socket

When more then one peer connected to a ZMQ_PAIR socket,
an application aborted due to assertion failure.
This patch changes the ZMQ_PAIR socket behaviour so that
it rejects any further connection requests.

The decoder did not properly decode large messages
on systems where sizeof (size_t) < sizeof (uint64_t).

Before this patch, the stream engine terminated itself
whenever it had detected an IO error. If this happened
when sending a message, the engine lost all
in-flight messages, messages waiting to be decoded,
and the last decoded message that had not been accepted,
if there was one.

The new behaviour is to terminate the engine only after
the input error has been detected and the last decoded

Tweak FD sockopt text

Added refinement for ZMQ_FD option

pipe: code cleanup

fq: remove unused parameter

The recv function accepted flags parameter but this was unused.

Mention limitation of the device implementation

+ fix whitespace errors
+ drop some unnecessary parens

Rename XREP/XREQ to ROUTER/DEALER in tests

xsub: fix memory leak

The implementation of the send call for XSUB socket failed
to release and initialise empty message when duplicate
subscription was detected.

Atomic operations for armv7a

This commit implements atomic operations for the armv7a architecture
using gcc inline assembly.  This offers higher performance compared to
pthread mutexes.

Tested on an am3517 evm, clocked at 600MHz:

./inproc_thr 200 1000000
------------------------
53-60K messages / sec, pthread mutexes
73-90K messages / sec, assembly atomic ops

./inproc_lat 200 1000000
------------------------
average latency: 42.234 [us], pthread mutexes
average latency: 35.496 [us], assembly atomic ops

add process_commands() to the beginning of zmq_connect() and zmq_bind()

I believe there was a conception that zmq_connect() and zmq_bind() will be called
only at the socket creation time and therefore don't need it.
Now it is not true anymore.

ZMQ BUG FOUND + fixes for zmq_unbind() / zmq_disconnect() usage corner cases