Update react-responsive to the latest version 

Try using headless chrome for integration tests

Minor fixes to sprite library

Update chromedriver to the latest version 

Update scratch-paint to the latest version 

Merge pull request #1578 from LLK/greenkeeper/scratch-vm-0.1.0-prerelease.1520372503-prerelease.1520372519

Update scratch-vm to the latest version 

Move backdrop library back to costumes tab

Add switching to costumes tab to surprise button also. All backdrop adding buttons should switch tabs.

Update deps 3/6

Closes #1515

Closes #1533

Merge pull request #1566 from LLK/greenkeeper/scratch-vm-0.1.0-prerelease.1520269961-prerelease.1520269983

chore(package): update scratch-vm to version 0.1.0-prerelease.1520269…

Switch to the correct costume number when switching sprites

Allow http url in import modal

Update scratch-paint to the latest version 

Performance audit of react/redux state

Update scratch-blocks to the latest version 

Cache Renderer.isSupported because it takes 30ms every time and breaks if called too often

Closes #1534

Update scratch-paint to the latest version 

Update scratch-paint to the latest version 

Swapping out default project with sb3 version.