Fix error after using Blob instead of BlobBuilder.

Error was: 'first argument of constructor in not of type array'
Thanks to:
http://www.nczonline.net/blog/2012/06/05/working-with-files-in-javascript-part-5-blobs/
Now it works for me.
Merge pull request #2 from Grahack/patch-1

Fix error after using Blob instead of BlobBuilder. thanks Grahack