Merge pull request #2297 from LLK/smoke

.travis.yml

package.json

src/containers/gui.jsx

src/containers/project-loader.jsx

src/lib/libraries/backdrops.json

src/lib/libraries/costumes.json

src/lib/libraries/sounds.json

src/lib/libraries/sprites.json

src/lib/project-loader-hoc.jsx

src/playground/intl.js

test/helpers/selenium-helper.js

test/smoke/browser.test.js