Manually merge release into master

cms/envs/aws.py

cms/envs/bok_choy.py

cms/envs/common.py

cms/envs/devstack.py

cms/envs/devstack_optimized.py

cms/envs/test.py

cms/startup.py

cms/static/sass/_build-v2.scss

cms/static/sass/_build.scss

cms/static/sass/_config.scss

cms/static/sass/_variables.scss

cms/static/sass/studio-main-rtl.scss

cms/static/sass/studio-main-v2-rtl.scss

cms/static/sass/studio-main-v2.scss

cms/static/sass/studio-main.scss

cms/templates/base.html

cms/templates/ux/reference/index.html

common/djangoapps/contentserver/admin.py

common/djangoapps/contentserver/middleware.py

...apps/contentserver/migrations/0002_cdnuseragentsconfig.py