Also include babel-core bridge for Jest itself, which depends on Babel 6.

Dynamic import didn’t do what we wanted, so just added `npm run i18n:msgs` to the start command. This is just temporary. Other changes as requested:
* exports in one place
* loc=> locale

Also fixed use of require for localeData to use dynamic import (this one works), so the babelrc changes are needed, otherwise import as a function is not recognized.

Generating the localization source to update the translation system (transifex) is really separate from building. When building we want to be using the current state of translations from transifex, and the english default strings are not needed.

Uses the babel-cli to run the babel-plugin-react-intl separately from  webpack.

WIP getting a react test working. Throws syntax error on svgs so need to maybe configure jest to use existing webpack config instead which probably properly handles svgs.
- added additional plugins to get tests working