Implemented a Structured Cloning Algorithm for the IndexedDB polyfill

This implementation add a capability to encode/decode objects of the following types:

 - Blob
 - Boolean
 - Date object
 - File object (deserialized as Blob object).
 - Number object
 - RegExp object
 - String object

Also was added a build process using Grunt which is explained on the README file. For better reviewing ignore the file `indexedDB.polyfill.js` because now this file is auto-generated.