feat(package): Change entrypoint and add requires/exports for commonJS (like browserify) usage

Author: Mickael Valmier

index.js

@@ -0,0 +1,2 @@
+require('./angular-masonry');
+module.exports = 'wu.masonry';

package.json

@@ -1,7 +1,7 @@
 {
   "name": "angular-masonry",
   "version": "0.16.0",
-  "main": "angular-masonry.js",
+  "main": "index.js",
   "devDependencies": {
     "grunt": "^0.4.1",
     "grunt-cli": "^0.1.13",