Fix date parsing tests

Forgot to after changing return value from "value" to "label"
Add tests for backbone-relational dexie addon
(dexie addon) Support relations defined as strings

They have to be resolved against Backbone.Relational.store,
unfortunately
(dexie addon) Automatically determine store name when mapping models
Make sure arrays in partitioned data are sorted by ID

This guff would not be necessary if I was a competent functional
programmer or if javascript had sets.