Fix/build tool maps 25

Various tweaks to npm scripts and the build tool.

- Server no longer gets restart on bundle changes. This was never necessary, the issue was that the rebundling wasn't updating the bundle file on disk

- running the app in dev mode is now:
```
npm run start:dev
```
This will bundle assets, build bundles, watch for file changes and rebundle and serve up the app on port 3000
mocha-traceur still hasn't been fixed - I'd recommend just avoiding it / using your fork