Merge branch 'develop' into ask-wait-answer-blocks

package.json

src/components/gui/gui.css

src/components/stage/stage.css

src/components/target-pane/target-pane.jsx

src/containers/blocks.jsx

src/containers/extension-library.jsx

src/containers/paint-editor-wrapper.jsx

src/containers/target-pane.jsx

src/examples/compatibility-testing.jsx

src/lib/default-project/09dc888b0b7df19f70d81588ae73420e.svg

src/lib/default-project/3696356a03a8d938318876a593572843.svg

src/lib/default-project/5c81a336fab8be57adc039a8a2b33ca9.png

src/lib/default-project/739b5e2a2435f6e1ec2993791b423146.png

src/lib/default-project/83a9787d4cb6f3b7632b4ddfebf74367.wav

src/lib/default-project/83c36d806dc92327b9e7049a565c6bff.wav

src/lib/default-project/index.js

src/lib/default-project/project.json

src/lib/libraries/extensions.json

src/lib/libraries/extensions/index.js

src/lib/libraries/extensions/pen.png