Upgrade babel, storybook, fix transpiling, update npm hook usage

[travis]

While we're at it, tweak babelrc (and associated dependencies) to more closely match the transpiling config of the example addon here:

https://github.com/storybooks/storybook/tree/master/addons/notes

Transpiled code should no longer have imports in it, which makes it work in jest tests.

Use a prepare hook rather than a prepublish hook
Per deprecation warnings on the console.