Merge remote-tracking branch 'origin/master' into 1.6

doc/sphinx/_static/sphinx_design.css

doc/sphinx/book/box/box_error.rst

doc/sphinx/book/box/box_index.rst

doc/sphinx/book/box/box_introspection.rst

doc/sphinx/book/box/box_schema.rst

doc/sphinx/book/box/box_session.rst

doc/sphinx/book/box/box_space.rst

doc/sphinx/book/box/box_tuple.rst

doc/sphinx/book/box/index.rst

doc/sphinx/book/box/net_box.rst

doc/sphinx/book/index.rst

doc/sphinx/book/intro.rst

doc/sphinx/conf.py