Reviewed-by: Konstantin Osipov <kostja@tarantool.org>

Change sio_advance_iov to never modify iov vector in place.
This allows for reuse of this function in a raw event
loop, without fibers.

Minor cleanups.

Make memcached/noreply.test less race prone:
flush all command is running in the event loop, and sometimes
it doesn't get a chance to finish before we issue the next
command.

 * join fiber->ready and fiber->ifc into one fiber->state
 * create fiber_yield_timeout function
 * channel uses fiber_yield_timeout
 * ipc test doesn't use fiber.sleep

Move memcached to src/
Make iproto.m dependend on box/*, not vice versa.
Remove box_ prefixes from test suite names.
Initialize networking outside of box/.

This makes Box a step closer to being just a storage
layer for Tarantool.

Still some ugly deps since box/ continues to manage
local hot standby and memcached expire (todo: move it out).

drop some ev_watchers from fiber structure.

all functions use rlist: avoid spare foreaches

Move mod/box/ src/box. Fix broken packages.
Rename tarantool_cpack.cmake to cpack.cmake.

Change memcached, admin and iproto connection to use the
buffered IO.
Make coio_writev accept a hint about the total size.
Remove fiber iov.

https://bugs.launchpad.net/tarantool/+bug/1061147

Patch contributed by Mons Anderson

When accessing Lua stack via a numeric index, first calculate
absolute value of the index.

Make all subsystems (administrative console,
replication, memcached, binary protocol) use exception-based
socket API (sio.m).

Remove all fiber members related to socket I/O.
Remove fiber->peer and fiber->cookie.
The idea of the cookie is to preserve in the WAL
the originator of the request. This information is, however,
lost when saving a snapshot. To my knowledge there is no use
of this functionality, apart from pretty-printing
the WAL.

Peer is like cookie, but is textual and is used
for logging. However, now, as long as network errors
occur outside fiber context, most of the usefulness
is lost. The only remaining case is when someone is
trying to execute a write request on a read-only port.

For all other cases, sio.m already supplies SocketError
with peer name, and this is where it's most useful.