🤭 Make create-react-class and prop-types external modules 🤫
🤭 Make create-react-class and prop-types external modules 🤫

In #11, we added support for React 16. As part of that upgrade, we were
required to import two new npm packages to maintain backwards
compatibility: create-react-class and prop-types.

Because react-mobiledoc-editor is compiled for distribution using
webpack, any dependencies will be “inlined” into the final output
unless they are explicitly marked in the webpack config as external.

I forgot to make these two new dependencies external.
This caused react-mobiledoc-editor to inline its own copies of these
two packages instead of loading them from node_modules at runtime.

This is problematic for a number of reasons, but one of the most
obvious is that it meant that create-react-class was running in
production mode while end users were probably running React in
development mode. This manifested itself as spurious warning messages
about getDefaultProps being deprecated, which is in fact still
supported by create-react-class.

Fixes #12
upworthy/react-mobiledoc-editor