Implement role.grant(), add tests, misc renames.
gh-488 setuid functions

Implement functions which change their effective
user id ot the one of the definer during execution.
Update a changed test.
Fix #394: LuaJIT doesn't work under Valgrind 3.9.0+
Remove objc include from cmake/luajit.cmake
Merge branch 'stable'
Revert LuaJIT update due to failed box/tuple.test.lua
Bug fix update for LuaJIT
Merge branch 'stable'

Conflicts:
	third_party/luajit
Add check for valgrind/valgrind.h include file.
Merge branch 'master' of https://github.com/tarantool/tarantool