Small code simplification

Fix a bug in trie implementation

When removing keys for a specified value, make sure we drop
empty node table. Failing to do this can lead to asserion failure.

Refs: http://lists.zeromq.org/pipermail/zeromq-dev/2012-June/017589.html

declare struct iovec

avoids warnings of the form:

warning: 'struct iovec' declared inside parameter list
warning: its scope is only this definition or declaration, which is probably not what you want

when building downstream projects

Fix missing ENETRESET for Jira #LIBZMQ-329.

Missing semi-colon makes Windows compilation fail, Missing files in WIndows solution file

Add errno fallback values for MSVC2008.

Reworked ZMQ_FAIL_UNROUTABLE to actually work as it was intended.

Fix open_socket to return -1 (INVALID_SOCKET on Windows) on error

Connecter cleanups

Calling close () when the underlying socket is invalid
triggers an assertion failure.

Make start_connecting () to have singe exit point.

The patch is meant to make the code easier to understand.
The 'wait' attribute is replaced by 'delayed_start'
and 'timer_started' attributes. The former is constant and
is initialized in the constructor. The latter is a flag
reflecting whether a timer has been started and changes during
the lifetime of the object.

current libzmq not compiling with android NDK

- Android crosscompiler shows a warning about two signed/unsigned checks
  on compilation, this patch adds casts to avoid this, so zmq3.x can
  compile on it.

Correct typo: add missing single quote.

Fix #LIBZMQ-329 assertion on WSAEACCES

{tcp|ipc}_listener: close socket when set_address () fails

Add unistd header to test

For sleep and usleep

Add newline to end of new test file

Add ZeroMQ branding.

Add ZMQ_DELAY_ATTACH_ON_CONNECT sockopt

Update bind and connect documentation for clarity

Rename the pipeset to terminating_pipes, as suggested by Martin H. Adds
asserts to test the pipe is contained in the terminating set where
appropriate.