Resolve LIBZMQ-459

Ref: https://zeromq.jira.com/browse/LIBZMQ-459

Older versions of C compilers don't like C++ comments

There's no need to exclude older compilers by putting C++ style
comments in the C API header.

Update builds/msvc/libzmq/libzmq.vcproj

Without the LinkDLL statement, command-line compile using vcbuild attempts to compile EXE and complains about entrypoint
The LinkDLL statement forces the linker to produce desired output

Resolve LIBZMQ-464

zmq_getsockopt man page was malformatted

Style fixes

Resolve LIBZMQ-458

Ref: https://zeromq.jira.com/browse/LIBZMQ-458

New socket option (ZMQ_ROUTER_RAW_SOCK) for ZMQ_ROUTER sockets

Use correct types when returning value in read/write methods

Resolve LIBZMQ-447

    - Created a new option ZMQ_ROUTER_RAW_SOCK
    - Added new raw_encoder and raw_decoder to receive and send messages in raw form to remote client
    - Added test case file tests/test_raw_sock.cpp

    o To create a raw router sock set the ZMQ_ROUTER_RAW_SOCK option
    o ZMQ_MSGMORE flag is ignored for non-id messages
    o To terminate a remote connection send id message followed by zero length data message

Fixed code formatting

resolve issue 456

Do not filter out duplicate subscriptions on the XSUB side of
XSUB/XPUB, so that ZMQ_XPUB_VERBOSE doesn't get blocked by forwarding
devices (as long as the devices all use ZMQ_XPUB_VERBOSE)

Cleanups to man pages

Resolve LIBZMQ-452

Resolve LIBZMQ-417

Ref: https://zeromq.jira.com/browse/LIBZMQ-452

Ref: https://zeromq.jira.com/browse/LIBZMQ-417

Fix Build Regression #449: Move socket_base.hpp and err.hpp after poll.h include

These two headers also include zmq.h somewhere in their dependency
chain, so must be included after poll.h is included for builds to work
on AIX.

Fixed whitespace and style

Fixed build regression #449