Formatting of multiple models

Workaround for when there are multiple instances derived from a same
model that will have clashing key/value pairs e.g tenant_(one|two)
Renamed defendant fields in the PDF form
Claim#as_json redone

So that the formatting of all the model's attributes is
easier to create for PDF population
Defendant data JSON format done
Notice#as_json done
Order#as_json addressed
Date formatting done
Removed DemotedTenancy

Not required any longer and is being replaced by another model
Merge pull request #20 from ministryofjustice/multiple-tenants

Models' as_json done