Merge pull request #1481 from kchadha/sb2-import

src/components/close-button/close-button.css

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

src/components/close-button/icon--back.svg

src/components/gui/gui.jsx

src/components/import-modal/import-modal.css

src/components/import-modal/import-modal.jsx

src/components/preview-modal/preview-modal.css

src/components/preview-modal/preview-modal.jsx

src/containers/gui.jsx

src/containers/import-modal.jsx

src/containers/preview-modal.jsx

src/css/colors.css

src/reducers/modals.js

test/integration/project-loading.test.js