Added unbind/disconnect man pages, notes to deprecated methods

doc/Makefile.am

-MAN3 = zmq_bind.3 zmq_close.3 zmq_connect.3 zmq_proxy.3 \
+MAN3 = zmq_bind.3 zmq_unbind.3 zmq_connect.3 zmq_disconnect.3 zmq_close.3 \
     zmq_ctx_new.3 zmq_ctx_destroy.3 zmq_ctx_get.3 zmq_ctx_set.3 \
-    zmq_init.3 zmq_term.3 \
-    zmq_msg_close.3 zmq_msg_copy.3 zmq_msg_data.3 zmq_msg_init.3 \
-    zmq_msg_init_data.3 zmq_msg_init_size.3 zmq_msg_move.3 zmq_msg_size.3 \
+    zmq_msg_init.3 zmq_msg_init_data.3 zmq_msg_init_size.3 \
+    zmq_msg_move.3 zmq_msg_copy.3 zmq_msg_size.3 zmq_msg_data.3 zmq_msg_close.3 \
     zmq_msg_send.3 zmq_msg_recv.3 \
-    zmq_poll.3 zmq_recv.3 zmq_send.3 zmq_setsockopt.3 zmq_socket.3 \
-    zmq_socket_monitor.3 zmq_strerror.3 zmq_version.3 zmq_getsockopt.3 zmq_errno.3 \
-    zmq_sendmsg.3 zmq_recvmsg.3 zmq_msg_get.3 zmq_msg_set.3 zmq_msg_more.3
+    zmq_send.3 zmq_recv.3 \
+    zmq_msg_get.3 zmq_msg_set.3 zmq_msg_more.3 \
+    zmq_getsockopt.3 zmq_setsockopt.3 \
+    zmq_socket.3 zmq_socket_monitor.3 zmq_poll.3 \
+    zmq_errno.3 zmq_strerror.3 zmq_version.3 zmq_proxy.3 \
+    zmq_sendmsg.3 zmq_recvmsg.3 zmq_init.3 zmq_term.3
+
 MAN7 = zmq.7 zmq_tcp.7 zmq_pgm.7 zmq_epgm.7 zmq_inproc.7 zmq_ipc.7
 
 MAN_DOC = $(MAN1) $(MAN3) $(MAN7)

doc/zmq_recvmsg.txt

@@ -26,6 +26,8 @@ Specifies that the operation should be performed in non-blocking mode. If there
 are no messages available on the specified 'socket', the _zmq_recvmsg()_
 function shall fail with 'errno' set to EAGAIN.
 
+NOTE: this API method is deprecated in favor of zmq_msg_recv(3).
+
 
 Multi-part messages
 ~~~~~~~~~~~~~~~~~~~

doc/zmq_sendmsg.txt

@@ -36,6 +36,7 @@ NOTE: A successful invocation of _zmq_sendmsg()_ does not indicate that the
 message has been transmitted to the network, only that it has been queued on
 the 'socket' and 0MQ has assumed responsibility for the message.
 
+NOTE: this API method is deprecated in favor of zmq_msg_send(3).
 
 Multi-part messages
 ~~~~~~~~~~~~~~~~~~~