Update start page copy

 - title
 - body
 - description
Rephrase question titles and respective node keywords
Fix dates because using Date.today will bite us in the future
Add helper methods to calculator for uprating values

These values will be used in the outcomes to work out the weekly
allowance provided to citizens.
Whitespace cleanup
Provide a way to work out when payment should start
Simplify salary calculations to use new uprating values
Continue with April 7th changes
Silly comparisons with Money classes
Copy and outputs for maternity test
Fix bug with passing money objects into money.new
Fix formatting fix
Merge pull request #286 from alphagov/calculate-your-matenity-pay-uprating-and-copy

Calculate your maternity pay uprating and copy