Fix && syntax /cc @hedgerh

package.json

@@ -5,16 +5,16 @@
   "main": "index.js",
   "scripts": {
     "browser-sync": "browser-sync start --config bs-config.js",
-    "build": "npm run build:js & npm run build:css",
+    "build": "npm run build:js && npm run build:css",
     "build:css": "bin/styles",
     "build:js": "bin/scripts node_modules/.bin/browserify",
     "build:examples": "examples/buildAll",
-    "clean": "rm -rf build/*.js & rm -rf build/*.css",
+    "clean": "rm -rf build/*.js && rm -rf build/*.css",
     "lint": "eslint src/js/lib/**/*.js",
     "phantom-test": "zuul test/spec/upload.js --phantom",
     "preview": "npm run watch & npm run browser-sync",
     "test": "bin/test",
-    "watch": "npm run watch:css & npm run watch:js",
+    "watch": "npm run watch:css && npm run watch:js",
     "watch:css": "nodemon -e scss -x \"npm run build:css\"",
     "watch:js": "bin/scripts node_modules/.bin/watchify"
   },