Make sure we do not have pending updates prior to turning
on remote recovery.

Get rid of the boolean variable 'box_updates_allowed'
and pass a function pointer to iproto_interact
instead (one less 'if' on the way of the most common
execution flow).

Remove diagnostics.[hm] since we should use
Objective C exceptions going forward.

A few more cleanups related to v03/v04 snapshot/wal
format.

Basic cleanup that removew old/unused code.

Send error messages to the client.

Before this patch, Tarantool would only send an error
code to the client, but record all the details in its error log.

This patch extends the client/server protocol and adds
error text to it. This text can now contain not only
a staple message that corresponds to the error, but
problem-related additional information, such as namespace id,
field number, etc.

All errors still can be logged in the error log, but
not all of them need to be. For errors, which are only
sent to the client, this patch uses ClientError exception
class. Errors which also need to be logged in the error log
must use LoggedError exception class.

To choose between the two, the following rule of thumb is applied:
- client application errors, which, generally, can be non-errors at all,
  such as access to a non-existing namespace, index or field, or
  access to a locked tuple are not logged
- execution and protocol errors, such as an error writing to disk,
an message that doesn't follow the protocol format, is logged.

For the most common error, ER_TUPLE_IS_RO, we do not use
string template to reduce CPU cycles necessary to produce this error
(on my machine one can raise ~200 000 exceptions per second, which is not
too much).

An addition to the above, this patch renames error codes, to
make them shorter (ERR_CODE_* -> ER_*) and rewrites the iproto.m
client connection loop to make it a trifle more efficient.

This patch also fixes a couple of bugs:
- in exception.m, [tnt_Exception alloc]
when we reused the old exception class, we did
not reset its 'isa' pointer, which could lead to a crash
when a message with a different signature was sent to
it.

- in box_dispatch (renamed from box_dispach),
when logging for slow commands was done, txn->op could
already be overwritten by txn_commit()/txn_abort().

A comment on the naming scheme: prefixing every Tarantool
piece of method/data structure with tnt_ would lead
to very bloated code. So in this patch
I decided to reduce the use this
prefix to the client library code and some very
generic names only.

When stopping the server under gdb, send SIGTERM
to the server, not to the terminal in which
gdb is started. This gives you the option
to actually examine gdb output before the test
has ended.

When the server crashes, and we're reading
from it in a client connection, detect EOF
and abort reading (the old code was buggy
and would busyloop indefinitely in case of
a crash).

Remove an unnecessary fork() in
start().

When ctrl-c is pressed on the terminal, a signal (SIGINT)
is sent to all members of the foreground process group.

Since both wal_writer and logger processes' default action
on SIGINT is to terminate, they could terminate before parent.

This led to rather nasty results: in the circumstances, when
the parent somehow ignored SIGINT (e.g. under GDB), or handled
it after its children (a race condition), children would
disappear before parent, then parent would detect that
wal_writer is gone, try to panic/write to the log, which
is also gone, and on top of SIGINT get a SIGPIPE.

Move spawned children to their own process groups
to make sure they don't belong to the main process'
process group, and don't receive signals from the
controlling tty. It's okay in the interactive mode,
since these children are going to die anyway when the
parent dies, after getting a SIGPIPE.

Do not try to start another server on a port if it's already in use.
This can lead to very confusing results when running
tests that start and stop the server in parallel.

Remove an extra space in '-e ' option to term,
not all terminals (rxvt, for example) can handle the extra
space in an option name.

Update *.cfg files to newer confetti and comments
in the templates.

Rename exceptions.[hm] to exception.[hm]. Add copyright
information.

There were extra quotes in errcode.c, i.e.
quotes were part of the error message.
Remove them.

Sweep out the first set of coding bugs in the test suite:
- set slab_alloc_arena to 0.05 in all box_replication configurations,
since otherwise this suite tries to allocate too much memory
and hangs under a VM.
- update some texts that make it into the log (spelling)
- add logging to all configurations
- simplify wait_sync and rename it to wait_lsn
- there was a bug in wait_sync that time.sleep() was
not called in the body of the loop due to \t, and
the loop was a busy-wait one.

If fiber_connect() is aborted with tnt_FiberCancelException,
an assertion in fiber_close() could fail that fiber->io is active
(it was not active).

The fix is to check in fiber_close() whether or not fiber->io
is active before closing it.

Conflicts:
	mod/box/box.m

Code review: reformat comments.
Add comments to fiber.h.
Use tnt_FiberCancelException solely to cancel fibers.
Fix alignment of fiber_server.
Use newer confetti.

Reverse the try/finally wrapping of some fiber functions
as unnecessary.

Tweak my previous patch for proctitle to be a bit
more robust to the path length.

Start pruning Tarantool wiki on github, and add documentation
on Tarantool process title to the user guide, since
it is present on the wiki but not in the user guide.

While at it, make the process title more lookalike on Linux
and FreeBSD, and rename some of the (what looks to me as) unclear
process titles.
The documentation reflects the new naming scheme already.

Move Ruby connector to its new destination (connector/).

Extend language-reference.xml.
Minor edits of salloc.m.

Document memcached options. Tweak doc/sql.txt.

Add sql.txt, describing the supported SQL grammar,
to which the user guide refers.

Add more content to the user guide (language reference, memcached support).

Learn how to use olinking correctly.
Add errcode.xml - the list of all error codes.
While at it, add markers to errcode.h signalling
that whenever it is changed, errcode.xml also needs a change.
Get rid of ERR_CODE_UNKNOWN_ERROR - it has no raison d'être.

Tweak the docbook to html XSL rules, in particular
table of contents generation.

Explain how to configure a namespace.
Tweak some error messages on the way.

Adjust signature of tbuf_ltrim, add comments,
replace a check with an assert.

tbuf: tbuf_ltrim function was added.
admin: admin_dispatch routine was fixed. fiber read buff managment was changed
       from peek to trim.