Refactor build routine and switch to airbnb style (#1703)

- Relocate webpack stuff to assets/build
- Switch all js to airbnb code style
- Update webpack to v2.0 (beta)
- Update all other dependencies
- Assets manifest uses relative path as key [1]
- Code should be compatible with Node 4.5.0
- All dependencies have been updated

[1]: Previously the assets manifest would use the basename of a file path as
its key when looking up a cachebusted file. This was to be consistent with
Sage 8. This change makes it so that the relative path is used instead.

To clarify, review the following example.

Before:
```
{
  "main.js": "scripts/main_5f4bfc9a9f82291c6dea.js",
  "main.css": "styles/main_5f4bfc9a9f82291c6dea.css",
  "customizer.js": "scripts/customizer_5f4bfc9a9f82291c6dea.js"
}
```

After:
```
{
  "scripts/main.js":"scripts/main_5f4bfc9a9f82291c6dea.js",
  "styles/main.css":"styles/main_5f4bfc9a9f82291c6dea.css",
  "scripts/customizer.js":"scripts/customizer_5f4bfc9a9f82291c6dea.js"
}
```

assets/scripts/customizer.js

@@ -1,5 +1,5 @@
 import $ from 'jquery';
 
 wp.customize('blogname', (value) => {
-  value.bind((to) => $('.brand').text(to))
+  value.bind((to) => $('.brand').text(to));
 });

assets/scripts/main.js

@@ -1,12 +1,12 @@
 // import external dependencies
-import 'jquery'
-import 'bootstrap/dist/js/bootstrap'
+import 'jquery';
+import 'bootstrap/dist/js/bootstrap';
 
 // import local dependencies
 import Router from './util/router';
 import common from './routes/Common';
 import home from './routes/Home';
-import about_us from './routes/About';
+import aboutUs from './routes/About';
 
 // Use this variable to set up the common and page specific functions. If you
 // rename this variable, you will also need to rename the namespace below.
@@ -15,8 +15,8 @@ const routes = {
   common,
   // Home page
   home,
-  // About us page, note the change from about-us to about_us.
-  about_us
+  // About us page, note the change from about-us to aboutUs.
+  aboutUs,
 };
 
 // Load Events

assets/scripts/routes/About.js

@@ -1,5 +1,5 @@
 export default {
   init() {
     // JavaScript to be fired on the about us page
-  }
+  },
 };

assets/scripts/routes/Common.js

@@ -4,5 +4,5 @@ export default {
   },
   finalize() {
     // JavaScript to be fired on all pages, after page specific JS is fired
-  }
+  },
 };

assets/scripts/routes/Home.js

@@ -4,5 +4,5 @@ export default {
   },
   finalize() {
     // JavaScript to be fired on the home page, after the init JS
-  }
+  },
 };

assets/scripts/util/camelCase.js

@@ -0,0 +1,5 @@
+// the most terrible camelizer on the internet, guaranteed!
+export default (str) => `${str.charAt(0).toLowerCase()}${str.replace(/[\W_]/g, '|').split('|')
+  .map(part => `${part.charAt(0).toUpperCase()}${part.slice(1)}`)
+  .join('')
+  .slice(1)}`;

assets/scripts/util/public-path.js

@@ -1,8 +0,0 @@
-/* globals WEBPACK_PUBLIC_PATH */
-
-// Dynamically set absolute public path from current protocol and host
-if (WEBPACK_PUBLIC_PATH !== false) {
-  /* eslint-disable no-undef */
-  __webpack_public_path__ = location.protocol + '//' + location.host + WEBPACK_PUBLIC_PATH;
-  /*eslint-enable no-undef*/
-}

assets/scripts/util/router.js

@@ -6,6 +6,8 @@
  * replace the dash with an underscore when adding it to the object below.
  * ======================================================================== */
 
+import camelCase from './camelCase';
+
 // The routing fires all common scripts, followed by the page specific scripts.
 // Add additional events for more control over timing e.g. a finalize event
 export default class Router {
@@ -25,10 +27,15 @@ export default class Router {
     this.fire('common');
 
     // Fire page-specific init JS, and then finalize JS
-    document.body.className.replace(/-/g, '_').split(/\s+/).forEach((className) => {
-      this.fire(className);
-      this.fire(className, 'finalize');
-    });
+    document.body.className
+      .toLowerCase()
+      .replace(/-/g, '_')
+      .split(/\s+/)
+      .map(camelCase)
+      .forEach((className) => {
+        this.fire(className);
+        this.fire(className, 'finalize');
+      });
 
     // Fire common finalize JS
     this.fire('common', 'finalize');