Integrate twitter typeahead with the sir-trevor widget for picking items

![screen shot 2014-02-13 at 10 33 34](https://f.cloud.github.com/assets/111218/2163304/641b3364-94dd-11e3-861e-54164499e40d.png)


The autocomplete data source is far from perfect.. we'll need to do some reindexing to get decent type ahead behavior... but this works ok.