Add @babel/plugin-transform-runtime

[vtaits]

#281

[taion]

do you have numbers on what this does for the bundle size? my impression is that the helpers compress really well, so the net benefit of runtime when we don't need its kind of polyfilling is quite low

[jquense]

It should be a clearer win with Babel 7 I think since the runtime doesn't polyfill anything by default anymore. But we should check

[vtaits]

I have screens before and after injecting this plugin to my project.

Before:

After:

But bundle contains also polyfills and used libraries.

If every library will import same helpers from @babel/runtime bundle size will more small.

[vtaits]

With react-overlays: 280K before, 272K after.