• Correct SPDX license fields in the packages. The LICENSE files have always been BSD-3-Clause, but the license field was set to "MIT".
• The peerDependency on "react" is set to "*" in the react-dnd package, but 16.x is installed for development.
• This doesn't affect the packages, but the documentation was using some deprecated react/lib modules, and the react-hot-loader needed to be updated.