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.
Merge pull request #458 from vortechs2000/remove_cpp_comments_from_zmq_h

Older versions of C compilers don't like C++ comments
Resolve LIBZMQ-459

Ref: https://zeromq.jira.com/browse/LIBZMQ-459
Merge pull request #459 from hurtonm/issue_459

Resolve LIBZMQ-459
Renamed raw option to ZMQ_ROUTER_RAW
Merge pull request #460 from hintjens/master

Renamed ZMQ_ROUTER_RAW_SOCK to ZMQ_ROUTER_RAW
session_base: code cleanup

- add unlikely hints
- drop unnecessary assertion
- style fixes

There is no need to require the 'more' flag in the provided message
structure be 0 when pulling message from the session.
Merge pull request #461 from hurtonm/code_cleanup

session_base: code cleanup
Added DEALER-DEALER as legal combination
Extend ZMQ_ROUTER_RAW test

Add test when the zeromq socket connects to a TCP socket.
The test now fails due to bug in the zeromq library.
Never exchange identities for sockets in raw mode

Zeromq shall never send/receive socket identifiers for sockets in raw
mode. The existing implementation breaks this requirement after
reconnection.
Merge pull request #462 from hurtonm/raw_fixes

Fix raw mode on reconnect
Added ROUTER-ROUTER as legal combination
Don't forward identities to DEALER sockets
Use const_cast operator to remove const modifier
Small cleanups
Merge pull request #464 from hurtonm/code_cleanup

Code cleanup
Bring along CMake patchset from zeromq3-x for adding minor version to Windows labeling.
Update source list with raw codec.
Merge pull request #465 from steve-o/cmake-minor

Cmake minor version labeling and sync with 3.x