sync version of locator without plugins

As part of the effort to speed up the boot process of the app, to improve development productivity, we are moving away from the plugin architecture on locator in favor of more formal build processes using Grunt, Gulp or Broccoli. This will also help us to focus more on the core features of the locator, which are understanding the filesystem semantic and the bundles lookup. 

This PR address this by removing all plugin related features, and moving from a Promise base API to a regular sync API. Since there are a bunch of indentation changes, use this link for the diff: https://github.com/yahoo/locator/pull/23/files?w=1