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.