Correct flow for people born after 1992-04-05

If born after this date, you should be asked how many years of work you did when aged 16-19, instead of going directly to the results page.
Correctly calculate automatic credits in Q6

Previously, the automatic credit calculation was delayed until Q10.
Meaning Q11 was potentially needlessly asked.
Fix leap year calculation - days between two dates

There is no need to remove a day from whole_days_away. Ruby / Rails already gives the correct calculation.
Paternity leave should be mentioned before paternity pay
Additional paternity leave mentioned before additional pay
Merge pull request #1182 from alphagov/order-of-paternity-entitlements

Order of paternity entitlements
Split initial employment questions between birth and adoption
Merge pull request #1179 from karlentwistle/master

Fix bugs in state pension calculator V2

As discussed with @karlentwhistle future PRs will be on branches from alphagov/smart-answers. I've checked this fork out and tests all pass.
Merge pull request #1184 from alphagov/split-employment-pages

Split initial employment questions between birth and adoption
Copy changes SPL questions 07/10
Copy changes SPL snippets 07/10
Implement lower_earnings_start plugin
Copy changes SPL start page 07/10
Merge pull request #1185 from alphagov/content-changes-07-10

Content changes 07 10
Bump smartdown version to 0.5.4
Fix parser error in copy changes SPL start page 07/10
Refactor callable predicate to allow arity of 0

All callable predicates previously required an arity of 1, leading to things like `->(_)` dotted everywhere.
Changed some of the predicates in marriage-abroad-v2 flow to take advantage of this simpler syntax.
Merge pull request #1186 from alphagov/content-changes-07-10

Fix parser error in copy changes SPL start page 07/10
Return Money and Date objects from SPL plugins
Merge pull request #1187 from alphagov/smartdown-bump-date-format

Format dates and salaries plugin results