Merge branch 'master' into form-styles

__tests__/integration/mirador/companion_windows.test.js

__tests__/src/actions/window.test.js

__tests__/src/components/CompanionWindow.test.js

__tests__/src/components/OpenSeadragonViewer.test.js

__tests__/src/components/WindowMiddleContent.test.js

__tests__/src/components/WindowSideBarCanvasPanel.test.js

__tests__/src/components/WindowSideBarPanel.test.js

__tests__/src/reducers/windows.test.js

__tests__/src/selectors/index.test.js

locales/en/translation.json

src/components/App.js

src/components/CompanionWindow.js

src/components/OpenSeadragonViewer.js

src/components/WindowMiddleContent.js

src/components/WindowSideBarCanvasPanel.js

src/components/WindowSideBarPanel.js

src/components/WindowViewer.js

src/components/WorkspaceMosaic.js

src/containers/CompanionWindow.js

src/containers/OpenSeadragonViewer.js