2.0.0 Release

 - [x] hapi 8 updates
   - ~~We're still waiting on an updated version of [`lout`](https://github.com/hapijs/lout/) (see: https://github.com/hapijs/lout/issues/89)~~
 - [x] renamed the `/plugins` directory to `/server`
 - [x] renamed the `/test/plugins` directory to `/test/server`
 - [x] code convention updates
   - see: https://github.com/hapijs/hapi/blob/master/docs/Style.md
 - [x] moved `/models` directory to `/server/models`
 - [x] moved `/test/models` directory to `/test/server/models`
 - [x] using `Object.assign` via the `object-assign` polyfill for model constructors
 - [x] switch to using `hapi-mongo-models` instead of baking in the base model and server plugin