don't use extends for the default presets!

[millermedeiros]

it will make it harder to use things like webpack/browserify! (would need to mock the dependency)

after https://github.com/millermedeiros/esformatter/commit/e6dd57baddbfa950ee5d563987537ea50a78c811 we are able to define presets like:

module.exports = {
  extends: [
    require('esformatter-preset-dolor')
  ]
}

so no good reason to list the relative paths.