Add reference to source of angular bloodhound port

I use the term "inspired" loosely. I should also mention that when I created angular-bloodhound, I started with typeahead v0.10.2 with my own custom fix for an issue that existed in official Bloodhound. That issue was fixed with typeahead.js v0.10.3.
Unless you intend to merge updates from typeahead.js bloodhound to this angularized copy, you should make your users aware that they won't be getting the benefits of @jharding's continued work on typeahead.js/bloodhound