Solution: add API and ZMQ_EVENT_PIPES_STATS event which generates 2
values, one for the egress and one for the ingress pipes respectively.
Refactor the events code to be able to send multiple values.

Solution: add monitor event socket option

Solution: When pipe_t is freed (terminated) remove it from _endpoints member of zmq::socket_base_t. Resolves issue #3245.

Solution: extract functionality into send_routing_id

Solution: remove it

Solution: remove them

Problem: inconsistent naming style for private data members, conflicts with naming of local variables and member functions

Solution: apply and check _lower_case naming style for private data members

Solution: removed

Solution: applied clang-format

* Problem: excessive memory allocations around blob_t

Solution: redefine blob_t as a custom type, and use reference/move
semantics where possible

Solution: replaced by "routing id"

Solution: renamed routing_id fields in pipe_t, renamed ZMQ_CONNECT_RID to ZMQ_CONNECT_ROUTING_ID

Solution: replace by "routing id"

Solution: renamed routing_id fields in pipe_t, renamed ZMQ_CONNECT_RID to ZMQ_CONNECT_ROUTING_ID

Solution: replace by "routing id"

Solution: where change pipe hwm, send a command (new type pipe_hwm) to peer, so peer pipe can modify hwm thread-safely

Solution: revert change from #2299 to avoid bugs while we look for an
alternative and thread-safe solution

Solution: fix them

Solution: update to 2016

We do not use 'get' for getters.

Solution: rename to zmq_msg_routing_id () for public API.

Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.

Solution: specify these grants in the header of each source file.

Solution: update for 2015

Fixes #1320

When pipe::write succeeds, it takes control of the message's data buffer.
When it fails, it has not taken control. The caller should clean up the
message appropriately (msg::close).

Revert "linking fd to pipe identity via socket option"

This reverts commit fe3e8c5c.

Conflicts:
	include/zmq.h
	src/pipe.hpp
	src/session_base.cpp

The get_credential () member function returns
credential for the last peer we received message for.
The idea is that this function is used to implement user-level API.