Use Kernel#Float to raise on invalid values
Update error messages with info on half-hours
Floar isn't a thing, Float is.
Merge branch 'holiday_calculator_input_validation' of github.com:alphagov/smart-answers into holiday_calculator_input_validation
Moar Kernel#Float and Kernel#Integer value checking
Explain half-hour and half-day input in error messages
Merge branch 'holiday_calculator_input_validation' of github.com:alphagov/smart-answers into holiday_calculator_input_validation
add hints and error messages to all hours and minutes questions
Merge pull request #553 from alphagov/holiday_calculator_input_validation

Holiday calculator input validation