Add bsTagsInput angular directive & example for bootstrap3 with typeahea...

...d.

Just thought I'd throw this out there - I found it easier to implement the angular directive in a different (incompatible) way, but I think it's a bit cleaner and more "future proof" against changes in both bootstrap-tagsinput and typeahead.js.  If nothing else, hope this helps anyone else looking for how to get angular working with bootstrap3 & typehead.

When the set of tags for typeahead are dynamic, I'd recommend taking a look at https://github.com/twitter/typeahead.js/pull/220 and using that approach until v0.10 comes out with some sort of officially supported mechanism.