Use babel-preset-env to include the right plugins automatically

[Ilya Radchenko]

https://github.com/babel/babel/tree/master/experimental/babel-preset-env

This should be added to the blueprint and used instead of the individual plugins, which are more brittle since it's easy to miss some. This also adds the benefit of allowing the consuming user to easily tweak which version of Node they want to support without having to get too dirty with the plugins.

[Dave Wasmer]

Fixed on master