Update react-modal to the latest version 

Add paint editor

Add duplicate option for sprite selector menu

Update postcss-import to the latest version 

Update style-loader to the latest version 

Update to react 16!

These version together so track them together.

Add a setup file that configures the React adapter. Fix one deprecated usage for ProjectLoaderHOC tests.

There are some tests still broken, but these weren't called out by Enzyme.

Closes #708

Fix tests on Windows

Fix travis again by pinning chromedriver and selenium versions

Changed existing string ids to use the convention `<repo>.<component>.<identifier>`

Fixed issue causing right click to drag sprite. 

Add say and think blocks to the toolbox XML

Fix selenium tests

Update react-tabs to the latest version 

Update eslint-config-scratch to the latest version 

Resolves #676