Minor incremental progress
* Don't need a singleton client.
* Don't link GHKit
`YLBusiness` model class
The response from Yelp is slightly inconsistent with the
[documentation](http://www.yelp.com/developers/documentation/v2/search_api),
Business objects that come from the search service don't have a coordinate.
It would be unfortunate if we had to make ~11 calls per search just to display on a map instead of a list.
The harness app _will_ crash because we're still pretending that a `YLBusiness` conforms to `MKAnnotation`
Simpler hydration of business model objets.