Replace socket('AF_UNIX', 'SOCK_STREAM', 'ip') with
        socket('AF_UNIX', 'SOCK_STREAM', 0).

Fixes distributions with missing "ip 0 IP" line in /etc/protocols
(e.g. Arch Linux).

closes gh-856

Backport fix from tarantool/mysql by Anton Reznikov

Also fix :send() and :write()

open(, O_CREAT | O_DIRECT, ) creates a file and then fails with
EINVAL in case if the underlying filesystem doesn't support O_DIRECT.
This behaviour is stupid and unexpected.

socket.tcp_server() changes:

 * Set nice fibers names for listener and clients
 * Use only one address for bind
 * Return single socket instead of wrapper
 * Add opts = {} to arguments
 * Automatically remove UNIX domain socket on server:close()

Other changes:

 * Fix buggy port number parsng for ipv6
 * Add peer address to accept() results like recvfrom()

Fixes compatibility with third-party modules.

This patch also adds argument checking to all socket methods.

(fix httpd log messages)

This patch fixes out of bounds memory access in bit_iterator_init
for size == 0. The patch also optimizes bitset/index library to skip
useless iterations over empty keys.

Closes #425

Add a testcancel() call to iowait().
A test case will be added to 1.6, where it's easier to do.

This patch fixes logic of non-blocking tcp connect as it
described in man pages and Unix Network Programming vol.1.

The bug was in the test itself - lack of trailing 0
at the end..

Fix a build warning on FreeBSD i386

Update the user guide.