Generate options to ActiveRecord.find rather than raw SQL for finding records near a given location.

Fix bug: extraneous parameter was being passed to fetch_coordinates method by fetch_and_assign_coordinates.

Fix incompatibility with certain Rails versions: don't use Hash.from_xml (XmlMini) to parse Google response--some versions of ActiveSupport lowercase all hash keys.

Improve comments, rename 'assign_coordinates' method, add optional parameter to fetch_coordinates for query term method name.