Merge pull request #86 from VictorLowther/switch_from_foreigner_to_schema_plus

+2 - this is HOT stuff.  Good call on the Switch from foreigner to schema_plus gem.
Have snapshot.rb take over the last remaining unique functionality in deployments.rb.
i18n-ize the system deployment description.
Remove most references to snapshots from the documentation.
Remove snapshot unit test
Remove snapshots from the Crowbar API.
Hack up the API bindings to remove snapshot stuff.
Make finding the system deployment a bit more DRY