Merge branch 'develop' into greenkeeper/react-test-renderer-16.1.1

package.json

src/components/asset-panel/selector.css

src/components/close-button/close-button.jsx

src/components/icon-button/icon-button.jsx

src/components/language-selector/language-selector.css

src/components/sprite-info/sprite-info.css

src/components/sprite-info/sprite-info.jsx

src/containers/blocks.jsx

src/containers/sound-tab.jsx

src/containers/sprite-info.jsx

src/css/units.css

src/index.jsx

src/lib/layout-constants.js

src/lib/make-toolbox-xml.js

src/reducers/toolbox.js

test/helpers/selenium-helper.js

test/integration/examples.test.js

test/integration/test.js

test/unit/components/__snapshots__/icon-button.test.jsx.snap

.../unit/components/__snapshots__/sound-editor.test.jsx.snap