add proxy_chain, a multi proxies chaining in the same thread feature

Man page fixes

add a proxy hook

Fixes to test cases

- renamed test_stream_disconnect_notifications (too long!)
- removed print statements in that test case
- fixed Makefile.am for test_zap_ipc_creds (was not building)

typo fix: RECVHWM -> RCVHWM

Changed fail behavior of CONNECT_RID to an assert failure instead of silent failure.

Added assert on duplicate id in ROUTER and STREAM sockets.  Updated man to reflect this change.  Modified test case to match.

Cleaned up formatting of test_connect_rid.  Set LINGER to 0 on sockets.  This may address the test failing on some devices.

factorize code in proxy

Added test_connect_rid

Fix compilation of tests on MSVC 2008

ZMQ_CONNECT_RID tests and man

Updated man entries, and added behavior in case the user duplicates peer ids.  In this case the socket reverts to default behavior.

Cleaned up option to force identity on outgoing connection

- renamed to ZMQ_CONNECT_RID
- fixed whitespace malformating around previous patch
- renamamed next_peer_id to next_rid in preparation for
  larger rename of IDENTITY to ROUTING_ID

Note: ZMQ_CONNECT_RID has no test case and no entry in the man
page, as yet.

Fixed compile issue with missing member of socket_base.  Changed ZMQ_NEX...

Fix cmake build and warnings

Fixed compile issue with missing member of socket_base.  Changed ZMQ_NEXT_IDENTITY to ZMQ_NEXT_CONNECT_PEER_ID.

Fixed case where ZMQ_NEXT_CONNECT_PEER_ID is used in ROUTER, and ROUTER does not read the identity message from the connected pipe.

Updated STREAM and ROUTER sockets to allow for pre-naming of outbound connections

Store socket FD after connect

Add STREAM connect notification.