sending to socket using iovecs implemented for POSIX platforms

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
iovec-based send implemented on Windows platform

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
iovecs used for sending by sp_stream

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Transport's send function can send two memory chunks

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
sp_chunk and sp_chunkref implemented

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
CT_ASSERT (compile-time assert) macro added

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Implementation of sp_msg with separate header and body

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
sending messages uses zero-copy now

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
receiving messages uses zero-copy now

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
With inproc transport no header parsing on recv side is needed

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Minor bug in SUB socket fixed

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Make survey pattern work well with inproc transport

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Gather/scatter arrays added to the API

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
functions for parsing/ensabling message headers added to individual socket types

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Support for zero copy messages added

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
sp_ prefixes changed to nn_ prefixes

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Warning about file descriptors added to nn_socket man page

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
File descriptor warning in nn_socket man page moved to RETURN VALUE section

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
Man pages adjusted to reflect changes to nn_sendmsg and nn_recvmsg

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
nn_allocmsg and nn_freemsg man pages adjusted

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>