Closes #1636

Update scratch-paint to the latest version 

Add more browsers to the unsupported list

Fixes #1460 

Added:
- Opera (including Opera Mini)
- Silk

Not Added:
- Vivialdi - appears to be ‘Chrome’ in `platform.name`

Update scratch-blocks to the latest version 

Fix proptype warnings for asset panel buttons

Don't prevent default on keyboard events

chore(package): update scratch-paint to version 0.2.0-prerelease.2018…

Merge pull request #1633 from LLK/greenkeeper/scratch-vm-0.1.0-prerelease.1521481406-prerelease.1521481427

chore(package): update scratch-vm to version 0.1.0-prerelease.1521481…

Hold scroll position on switching sprites

Update react-modal to the latest version 

Closes #1619

Closes #1628

Clean up some unused prop warnings

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

Closes #1603

Make sensing "key pressed" block input droppable

Fix reload button on error page 

Allow new sprite to propagate before selecting costume tab

Update scratch-paint to the latest version 

Save and Load sb3 projects

Merge pull request #1600 from LLK/greenkeeper/scratch-vm-0.1.0-prerelease.1520606673-prerelease.1520606691

Update scratch-vm to the latest version 

Update scratch-paint to the latest version 

Update react-style-proptype to the latest version 

Removing JSZip dependency. VM will unpack the zip (for now, until this functionality gets moved to scratch-storage).

Update scratch-blocks to the latest version