support nested namespaced models

[bjrmatos]

A directory like the following:

should output a nested namespace object

current output:

{ AnimalWithSomething: AnimalWithSomething,
  Contact: Contact,
  base: { PersonWithSomething: base.PersonWithSomething },
  accounts: {},
  'base.accounts': { Person: base.accounts.Person } }

expected output:

{ AnimalWithSomething: AnimalWithSomething,
  Contact: Contact,
  base: { 
    PersonWithSomething: base.PersonWithSomething
    accounts: {
     Person: base.accounts.Person
   }
 }