Merge branch 'develop' into greenkeeper/scratch-storage-1.2.0

package.json

src/components/alerts/alert.css

src/components/alerts/alert.jsx

src/components/alerts/alerts.jsx

src/components/backpack/backpack.css

src/components/backpack/backpack.jsx

src/components/gui/gui.css

src/components/menu-bar/login-dropdown.jsx

src/components/menu-bar/menu-bar.jsx

src/components/menu/menu.jsx

src/components/spinner/spinner.css

src/components/spinner/spinner.jsx

src/components/sprite-selector-item/sprite-selector-item.css

src/components/sprite-selector/sprite-list.jsx

src/containers/alert.jsx

src/containers/backpack.jsx

src/containers/sb-file-uploader.jsx

src/containers/sb3-downloader.jsx

src/containers/sprite-selector-item.jsx

src/containers/stage-selector.jsx