* ZMQ_PLAIN_SERVER, ZMQ_PLAIN_USERNAME, ZMQ_PLAIN_PASSWORD options
* Man page changes to zmq_setsockopt and zmq_getsockopt
* Man pages for ZMQ_NULL, ZMQ_PLAIN, and ZMQ_CURVE
* Test program test_security

Implement ZMTP/3.0 PLAIN mechanism

This implements protocol handshake.
We still need to design and implement 1) API changes so a user
can set username and password, and 2) a mechanism for engine
to authenticate users.

Some changes to building and packaging

Implement ZMTP/3.0 NULL mechanism

zmq_msg_close clarification in man pages

Experimental function zmq_recviov doesnt work correctly in a couple of c...

1) VSM - you cannot hand out the 'data' address as it was not allocated on the heap
2) for other messages the 'data' address cannot be handed out either, as it not the address
originally returned by malloc and hence cannot be passed to 'free'.
see msg.cpp
u.lmsg.content = (content_t*) malloc (sizeof (content_t) + size_);
....
u.lmsg.content->data = u.lmsg.content + 1;

So the function is changed to always malloc a data buffer and copy the data into it.
There is a possible optimisation using memmove for the non-VSM case but that is not done yet.

Fix return code redeclaration for platforms with SO_NOSIGPIPE

Fixed issue LIBZMQ-526

Fixed issue LIBZMQ-525

Throughput perf test was borked, fixed it

as I can see, these didn't work any more. At the very least, the command line
API was broken and forced the user to enter new, exotic arguments. Patches
should not break existing APIs. But also, the internals of these programs had
become weird.

If we want to build more complex performance tests, that's fine, but we should
make new programs, not break the old ones. We need minimal, safe performance
tests in 0MQ.

Also, the code was quite horrid. So it's gone. If anyone wants to bring it back
please make the code neat, and build new APIs instead of breaking the old ones.

Cheers
Pieter

contributors and doesn't reflect the real process. I've taken out all named
authors and referred to the contribution policy. Hopefully this will improve
the contributions to the man pages.

Interoperate with higher versions of ZMTP protocol

[#LIBZMQ-446] Silence error on setting PGM_TOS on REL 4.

[#LIBZMQ-446] Silence error on setting PGM_TOS due to some platforms raising an error at runtime. Noted are RHEL 4.

MSVC local_thr & remote_thr dependency fix

Add platform.hpp as project dependency to vc100 and vc110 projects for local & remote throughput tests.

Use state functions for message flow

The patch makes the code somewhat simpler and prepares it for
more complex initialization handshakes.

Refactor code so that messages go through engines

Small clarification about connect and ROUTER