Refactor app.js

Merge pull request este#439 from geoRG77/replace-autoprefixer-loader

Replace autoprefixer-loader

Rename i18n to intl.

Because intl is standard in JavaScript ecosystem. Also easier to type.

Ok, revert closures inside event handlers.

It’s ok, if component rerender is controlled with its props via
shouldComponentUpdate check.

PropTypes should be as strict as possible.

Otherwise, it doesn’t make sense to have them.

Bump 7.0.1

Bump 7.0.0

Bump 6.3.8

Bump 6.3.7