Port width and whitespace modules to plugins

src/plugins/width.js

@@ -0,0 +1,13 @@
+import _ from 'lodash'
+
+export default function () {
+  return function ({ addUtilities, config, e }) {
+    const utilities = _.fromPairs(_.map(config('width'), (value, modifier) => {
+      return [`.${e(`w-${modifier}`)}`, {
+        'width': value,
+      }]
+    }))
+
+    addUtilities(utilities, config('modules.width'))
+  }
+}