iobuf_init() needs to be called regardless of whether
iproto is initialized or not.

Do it.
Make provisions to make it possible to update readahead on the fly.

doc/{branch}/... -> doc/...
Master/Stable -> One-page/Multi-page

Update mans, docs.

A lot of resources still need to be updated (build scripts, etc).

Don't block the event loop in the interactive mode.
Fix a merge bug (remove a debug print out from the test system).

Conflicts:
	src/ffisyms.cc

Do not read or require tarantool.cfg. Accept all options
in the script itself. Split server reconfiguration so that
parts of the server can be reconfigured independently.
Remove dependency on confetti.

To configure the server at start, call

box.cfg{option1=value1, option2=value2}

To reset an option on the fly, do the same:

box.cfg{option=value1}

box.cfg is a Lua table with all existing options.

Make local hot standby the default and remove local hot
standby option [gh-231].
If neither primary nor admin port is specified, the server does
not get stuck in local hot standby mode, and becomes a master
immediately.

Incompatible changes:
- pid_file is nil by default, and the server does not create
a pid file by default.
- local_hot_standby option is removed
- log_level is now a dynamic option
- wal_mode is "write" by default
- box.cfg only prints non-nil options

Clean up a lot of garbage code in the test system.
Remove configuration file support from TarantoolServer
and Lua test preprocessor.

The patch also contains a few unrelated improvements in the
interactive mode (history support, ^D leads to exit).

@todo The patch disables region_gc in recovery, which
may lead to memory overconsumptions when recovering large
snapshots. This needs to be fixed separately.

@todo Remove all configuration files and confetti files
in a follow-up patch (not done in this patch to not clutter
it).

tarantool_box without arguments runs in interactive mode.
@todo:
    - log_level by default should be 'critical'
    - wal_mode by default should be 'none'
    - pid_file by default should be 'none'
    - readline should be called via coeio, to not block
    event loop while it's running

See rationale for this fix in gh-223
Remove on the same token a buch of dead code for sandboxing
and do a few renames.

In preparation of removal of confetti and switching solely to
Lua-based configuration file, reduce dependencies on struct tarantool_cfg
and reorder server initialization, so that it can happen after the event
loop has already been started.

Remove command line options:

--cfg-get
--check-config
--config
--init-storage

- these are gone forever, in preparation for config-less start.

--background --  move to tarantool.cfg for now, in the future
it will be part of Lua config.

Make #! mandatory - if the server is started without #!, it's
only possible to query its version or get startup help (--version
and --help are the only remaining supported options).

When #! is present, do not parse options, pass them wholly to the
script at hand.

Add helper scripts to test suites, to start/stop the server.
For now, the scripts are empty, in the future they will be
merged with a respective config file.

Conflicts:
	doc/user/lua-tutorial.xml
	doc/user/plugins.xml
	doc/user/stored-procedures.xml

 * Change format of xlog/snap files to MsgPack-based format
 * Update replication to use IPROTO protocol
 * Rework replica bootstrap to process snapshot by rows
 * Add support for composite rows in fio_batch
 * Fix iproto->sync in SUBSCRIBE command

Conflicts:
	doc/user/data-model.xml
	doc/user/tutorial.xml