Merge branch 'master' into sophia-index

cfg/core_cfg.cfg_tmpl

cfg/tarantool_box_cfg.c

cfg/tarantool_box_cfg.h

doc/user/configuration-reference.xml

doc/user/connectors.xml

doc/user/data-model.xml

doc/user/errcode.xml

doc/user/language-reference.xml

doc/user/lua-tutorial.xml

doc/user/persistence-architecture.xml

doc/user/plugins.xml

doc/user/replication.xml

doc/user/server-administration.xml

doc/user/stored-procedures.xml

doc/user/triggers.xml

doc/user/tutorial.xml

extra/rpm.spec.in

src/CMakeLists.txt

src/admin.cc

src/bootstrap.snap