Add win dev script.

Author: donmccurdy

.gitignore

@@ -2,4 +2,5 @@ node_modules
 .DS_Store
 **/bundle.js
 npm-debug.log
-build
+build
+examples/aframe-extras.js

package.json

@@ -11,6 +11,7 @@
   },
   "scripts": {
     "dev": "budo browser.js:examples/aframe-extras.js",
+    "dev:win": "live-server . --port=9966 & watch-exec -c 'browserify browser.js -d -o examples/aframe-extras.js' -w src",
     "build": "./scripts/dist.js && ./scripts/build.js",
     "dist": "./scripts/dist.js",
     "test": "karma start ./tests/karma.conf.js",