Reset the balance after new period start

The reason that the balance was not reset after the new period started was
that all of the values including the daily budget and the daily budget sum
were not recounted.

- implement the areOldValues method in the Budget class that returns a
  boolean of whether the new budget period started and the values need to
  be recalculated.
- Move the isInitialStartUp check method to the MainActivity and make it
  return a boolean of whether all of the start up pages were went through.
- Reimplement the getBalance() method to use the values when the daily
  budget was set and figure out the daysAfterDailyBudgetSet int variable
  that will be used in the balance formula.
- Reimplement the setDailyBudget method to put the values of when the
  daily budget was set.