add rpm packages for PostgreSQL and MySQL.
do not directly require mysql-devel and postgresql-devel
packages.
Rewrite tuple[x] and #tuple bindings using FFI
tuple[x] FFI bindings - minor changes

Do not return extra result from tuple:__index method.
tuple:pairs and tuple:next FFI bindings
Remove debug message from tuple_iterator_next
Temporary changes
Fix tests after merging tuple-methods-ffi

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

This patch replaces Lua/C bindings to iterator by FFI.
Optimize index functions for FFI iterator
Merge branch 'stable'
update pg and mysql module install prefix
update sophia submodule
Merge branch 'stable'
Implement a new version of select() API

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.
select-new-api-v2: review fixes
Reimplement select() using FFI
Replace index:iterator() API with Lua-compatible pairs()

This patch converts space:iterator() to be compatible with Lua
for-in loop conventions. The most important change is that
generating function now returns *state* as its first result:

    for _state, val in space.index[0]:pairs() do work(val) end

New syntax follows the best practices of Lua community and makes
index API to be more consistent with pairs() and tuple iterators.

This change partially restores pairs() logic as it was implemented
before 4987561559388c8c5d672d613d17dbf6cd2f890f.
Merge remote-tracking branch 'origin/master' into iproto-greeting

Conflicts:
	src/box/lua/schema.lua
	src/ffisyms.cc
	test/big/lua.result
	test/box/net.box.result
	test/box/session.result