Ensure Answer associated with Question #4084

When creating or updating a Response validate that the
Answer being set is one of the Answers associated with the Question.

This probably should be added to Surveyor as a validation but is included
here to address the #4084 issue going forward with Cases. If Surveyor is
ever changed to add this validation we should remove it here
(see TODO note above validate callback)
Raise error #4084

instead of using ActiveRecord validations
to ensure data integrity
adding household_units to person creation #2580
fixing failing tests #2580

Now a person has a household when created.
don't make a ppg_detail for a child #3286
ODE for CHILD_DOB for birth event #4111
Added assertion to match expectation #3286
Merge pull request #193 from NUBIC/change_3286_ppg_status_detail_should_not_be_created_for_children_participants

Don't make a ppg_detail record for a child participant #3286
Merge pull request #196 from NUBIC/bug_4111_data_extractor_for_birth_dob

ODE for CHILD_DOB for birth event #4111

Merging for inclusion into 1.7.0.rc1.
Merge pull request #174 from NUBIC/4084-ensure_answer_for_response_associated_with_question

Ensure Answer associated with Question #4084
Add rank to models #2580

centralized the find/create method for the person
household unit
Merge branch 'develop' into bug_2580_ensure_household_and_dwelling_units_are_properly_created_for_new_participants

Conflicts:
	app/models/operational_data_extractor/base.rb
	spec/models/operational_data_extractor/base_spec.rb
Merge pull request #188 from NUBIC/bug_2580_ensure_household_and_dwelling_units_are_properly_created_for_new_participants

adding household_units to person creation #2580
Merge branch 'develop' into 4009_lo_i_postnatal
Merge branch 'develop' into 4009_lo_i_postnatal

Conflicts:
	app/models/person.rb
	spec/models/person_spec.rb