Use Webpack configuration based on NODE_ENV instead of watch/no-watch

Also, move the `DedupePlugin` to the prod-specific section. [Webpack doc](https://webpack.github.io/docs/list-of-plugins.html#dedupeplugin) itself recommends to not run this outside of production.

Note that this currently breaks cross-OS support of `npm run build`. This will be fixed in a latter commit.

package.json

@@ -17,14 +17,14 @@
     "start-dev": "npm-run-all --parallel watch start",
     "build": "npm-run-all build:*",
     "build:font-awesome": "node scripts/build-fontawesome.js",
-    "build:webpack": "webpack -p",
-    "watch": "webpack -d --watch",
+    "build:webpack": "webpack",
+    "watch": "webpack --watch",
     "test": "npm-run-all -c test:* lint",
     "test:mocha": "mocha",
     "lint": "npm-run-all -c lint:*",
     "lint:js": "eslint .",
     "lint:css": "stylelint \"**/*.css\"",
-    "prepublish": "npm run build"
+    "prepublish": "NODE_ENV=production npm run build"
   },
   "keywords": [
     "lounge",

webpack.config.js

@@ -2,7 +2,10 @@
 
 const webpack = require("webpack");
 const path = require("path");
-const isWatch = process.argv.includes("--watch");
+
+// ********************
+// Common configuration
+// ********************
 
 let config = {
 	entry: {
@@ -54,12 +57,16 @@ let config = {
 		]
 	},
 	plugins: [
-		new webpack.optimize.DedupePlugin(),
-		new webpack.optimize.CommonsChunkPlugin("js/bundle.vendor.js"),
+		new webpack.optimize.CommonsChunkPlugin("js/bundle.vendor.js")
 	]
 };
 
-if (!isWatch) {
+// *********************************
+// Production-specific configuration
+// *********************************
+
+if (process.env.NODE_ENV === "production") {
+	config.plugins.push(new webpack.optimize.DedupePlugin());
 	config.plugins.push(new webpack.optimize.UglifyJsPlugin({
 		comments: false,
 		compress: {