Add Travis build against 1.3.0-beta.N

Approaching the Angular `1.3.0` release it would seem sensible to expose `angular-ui` to tests against `1.3.0-beta.N`

I'm not sure whether my approach to finding the latest `1.3.0-beta.N` is ideal but couldn't find a better way of constraining it whilst still avoiding the various build tags.

### Rationale 

The typeahead component has been broken since Angular `1.3.0-beta.11` but we have no visibility on this in `angular-ui`

Thoughts?