Seeds a tenant when it's created

Populates spree_roles, spree_countries, spree_states, spree_zones, and
spree_zone_members with the same data that new Spree stores are
poulated with when `rake db:bootstrap` is called.
Adds spec examples that perform a full checkout on a tenant
Create seeds without protection
Adds spec to prevent zone issue regression
Sets the default_county_id config value
Fixes checkout spec to work with Spree 1.3
Merge pull request #8 from railsdog/topic/seeds-edge

Forward ports jbrien/spree_landlord#19 to master