Try to always keep the tutorial in view despite screen height

revised alerts and spinner styling

Fix empty <MenuSection>

Update scratch-svg-renderer to the latest version 

Update scratch-vm to the latest version 

Update scratch-l10n to the latest version 

chore(package): update scratch-blocks to version 0.1.0-prerelease.154…

chore(package): update scratch-vm to version 0.2.0-prerelease.2018121…

Add onClick prop for the logo

Closes #4056

Closes #4055

Update scratch-paint to the latest version 

Update scratch-render to the latest version 

Update scratch-svg-renderer to the latest version 

admins will see author credits, not title editing field, in editor

Update sprite library with new assets

Update scratch-blocks to the latest version 

Make mousedown on the stage blur inputs, with @picklesrus

Make the git links in the README consistent

Add what’s new tutorial (hidden)

Update WeDo tutorial video

Toward LLK/scratch-www#2296

This allows us to take you to any destination when clicking the logo, or to do something else, or nothing at all.

If no handler is provided, the logo will not be clickable.

Issue #4006