User refactor

Use idiomatic ruby for User#hours_entered_for_day
    
REFACTORED User#expected_hours

    Decomposed expeted_hours into:
      work_days_between_dates(start,finish)
      first_scheduled_date_in_future?(date)
      never_worked?
      first_scheduled_date

      The code is negibly less performant but much more expressive. This
      can be refactored into a UserWorkload class along with
      User#target_hours_offset(date). As a bonus we now have an ability
      to add logic for holidays in User#work_days_between_dates


:::

As an aside, I couldn't get the tests to run at all unless I had a database.yml in xrono/config. Also, there were timeout errors in the cukes.