Add Utils module.
Tests for Utils module
Always save ArrayBuffers of data to store.

Chrome doesn't support Blobs in IndexedDB.
Add #getAsString method to IndexedDBStore
Add method #blobToJSON to Utils
Remove unused browser sniffing code
Deprecate Utils#arrayBufferToURL(), use Utils#toObjectURL instead
Change storage format in database to JS object.

Can be able to embed metadata such as date, filename, etc.