New version of location finder.

Old FBLocation class removed and replaced with LocationFinder class,
now in models. This contains the beginnings of a more complete (and
possibly faster) location hash and search paradigm that will be easier
to scale because it is better encapsulate. The method that converts
names to coordinates is part of this class, and so most of the lookup
logic has been removed from the controller, as is right. Will remove
more of it (e.g. distance functions, the fallback calls to geocoder)
soon.