Library tweaks

This won't work on a lot of browsers, but temporarily just target modern ones. (Robust solution is possible using classNames and refs)

Add USE_HEADLESS=no npm run test:integration option

Libraries Phase II

Thanks @towerofnix!

Including action-menu which was also giving one when the backdrop library opened.
Localize the costume library, I missed it while doing the other libraries.

Update scratch-blocks to the latest version 

They're spammy — happy to put this back but they were unhelpful while fixing tests IMO.

chore(package): update scratch-blocks to version 0.1.0-prerelease.152…

Reorder and add default arguments to gt, lt, eq blocks

Adjustments to string operator default arguments

Thanks @ericrosenbaum!

Fix integration tests failing due to Chrome update?

Pages no longer reload if you hit the same hash URL twice

Closes #1816

Use unique ids for the toolbox elements that change per sprite

Remove feedback form

Resolve issue with costume Button 4-b

Upload a sound file