Remove subtitle field

It's only used in tests and sample content
Remove test for Bridge of Death subtitle
Merge pull request #1050 from alphagov/remove-subtitle-feature

Remove subtitle field
Added content about dual nationals to start page
Merge pull request #1051 from lutgendorff/patch-5

Added content about dual nationals to start page
Updating Student Finder Forms smart-answer

Change v2 files to v1
Merge pull request #1055 from alphagov/switch_student_forms_to_published

Updating Student Finder Forms smart-answer
Changing simplified-expenses-checker v2 files into v1

This is due to be published 12th August
Updating state-pension-through-partner v2 to v1
Merge pull request #1056 from alphagov/publish_simplified_expenses_checker

Updating simplified-expenses-checker smart-answer
Merge pull request #1057 from alphagov/publish_state_pension_through_partner

Updating state-pension-through-partner smart-answer
Smartdown in smart answers application
Use Ruby enumerables for body and devolved_body
Documentation for both styles of smart answers

Smartdown in smart answers application

Documentation for both styles of smart answers
Draft and version status, upgrade smartdown to 0.0.4
Smartdown in smart answers application
Documentation for both styles of smart answers
Rename Smardown module, first rough attempt at making visualisation work
Fix description of multiple choice options
Correct labels for predicate rules