Merge remote-tracking branch 'origin/master' into sophia-gh-577

doc/user/configuration-reference.xml

doc/user/connectors.xml

doc/user/databases.xml

doc/user/lua-tutorial.xml

doc/user/plugins.xml

doc/user/preface.xml

doc/user/proctitle.xml

doc/user/replication.xml

doc/user/server-administration.xml

doc/user/stored-procedures.xml

doc/user/tutorial.xml

doc/www/content/doc/box-protocol.rst

doc/www/theme/static/pygmentize.css

doc/www/theme/templates/script

src/box/CMakeLists.txt

src/box/alter.cc

src/box/authentication.cc

src/box/box.cc

src/box/box.h

src/box/iproto.cc