Initial Snapshot value class

Has some attributes (steps, battery, background). Needs refactoring to
reduce code duplication in Reporter::Snapshot.
Add Audio record
Add equality to Audio records
Add Reporter::Snapshot#audio
More Location methods
Add Reporter::Snapshot#location

* Move #hash into Reporter::Record::Base
* Add equality methods to Reporter::Record::Location
Add Reporter::Record::Weather
Add Reporter::Snapshot#weather
Downcase CamelCase method names on Reporter::Record::Weather
Add Reporter::Record::Response class
Move common Response functionality to a base class
Add Token and MultipleChoice Response sub-classes
Add Reporter::Record::Response::Location
Update Response class descriptions in comments
Add Reporter::Record::Response::Numeric
Add Reporter::Record::Response::Note
Add Response.factory method
Add Reporter::Snapshot#responses
Add snapshots to dump fixture
Add Reporter::Dump#snapshots