Upgrade to babel 6 and enable transform-runtime

[cesarandreu]

See the following: babel is injecting helpers into each file and bloating my code!

You'll also need to pull in babel-runtime as a dependency.

[bvaughn]

Upgrading to babel 6 breaks eslint:
path/to/file:0:0: Cannot read property 'tokTypes' of undefined

Looks like this is known: babel/babel-eslint/issues/199, standard/standard/issues/348

[bvaughn]

I disabled eslint and went forward with the upgrade in a branch. I may have fat-fingered things somehow- I'm not a Webpack expert by any means- but after adding transform-runtime my dist increased from 68 KB to 91 KB.