docs(webpack): use rimraf to clean dist

closes #1393

Author: Foxandxss

public/docs/_examples/package.json

@@ -16,7 +16,7 @@
     "webdriver:update": "webdriver-manager update",
     "start:webpack": "webpack-dev-server --inline --progress --port 8080",
     "test:webpack": "karma start karma.webpack.conf.js",
-    "build:webpack": "rm -rf dist && webpack --config config/webpack.prod.js --progress --profile --bail"
+    "build:webpack": "rimraf dist && webpack --config config/webpack.prod.js --progress --profile --bail"
   },
   "keywords": [],
   "author": "",

public/docs/_examples/webpack/ts/package.webpack.json

@@ -5,7 +5,7 @@
   "scripts": {
     "start": "webpack-dev-server --inline --progress --port 8080",
     "test": "karma start",
-    "build": "rm -rf dist && webpack --config config/webpack.prod.js --progress --profile --bail",
+    "build": "rimraf dist && webpack --config config/webpack.prod.js --progress --profile --bail",
     "postinstall": "typings install"
   },
   "license": "MIT",
@@ -37,6 +37,7 @@
     "null-loader": "^0.1.1",
     "phantomjs-prebuilt": "^2.1.7",
     "raw-loader": "^0.5.1",
+    "rimraf": "^2.5.2",
     "style-loader": "^0.13.1",
     "ts-loader": "^0.8.1",
     "typescript": "^1.8.9",