This patch introduces backward-incompatible changes to select()
and adds couple new methods:

  * index:select(key) -> tuple, tuple, ... was changed to
    index:select(key, opts = {}) -> { tuple } where opts can be

       - iterator = ALL if key == nil or key == {} | EQ otherwse
       - offset = 0
       - limit = unlimited

  * index:get(key) -> tuple | nil | error on more than one tuple
    a wrapper for select() to get the single tuple

  * space:put(tuple) -> tuple
    an alias for space:replace() (to provide integrity with get())

Test suite, box.space and box.net.box API were also updated to
meet changes.

This patch replaces Lua/C bindings to iterator by FFI.

Minor changes - fix msgpack.decode for zero-size arrays and update
line numbers in result files.

Do not return extra result from tuple:__index method.

packages.

Marshall replication using the primary port.

Split iproto requests into two categories: DML and admin.  Change
PING request code to 64, to lay within admin request range.
Perform administrative requests synchronously, without pushing
them into an event queue.
Add a new administrative request, IPROTO_SUBSCRIBE.

Use dynamic memory for struct iproto_request. Introduce memory
management.

Remove replication_port from the configuration file and
update tests.

Fix the test runner so that it correctly generates
replication_source to point to the primary port.
Add variable arguments to IllegalParams.
Move replia-related recovery methods to a new header, replica.h.

Remove a debug printout from box.net.lua

Update tests.

Conflicts:
	.gitignore
	cmake/BuildMisc.cmake
	cmake/compiler.cmake
	include/avl_tree.h
	src/box/avl_tree_index.h
	test/unit/avl_tree.c
	third_party/qsort_arg_mt.c

'print_log'`

Conflicts:
	src/box/lua/box_net.lua
	test/box/ipc.test
	test/box/net.box.result

 + memory leak in box.net.box (timeouted responses)
 + remote:ping() never throw exception