- `package.json`: explicit path to `node_modules/.bin` isn't needed
since npm prepends it to `PATH`. See [nmp scripts
doc](https://docs.npmjs.com/misc/scripts#path).
- `.bowerrc`: [Bower's default
directory](http://bower.io/docs/config/#directory) is
'bower_components', hence no need to explicitly set it to this value.
Limitations because of preview status (see #960):
- does not yet use ShadowDOM
- does not use a builtin conditional like `if`
- uses a temporary bower repository
Closes#943