Added zeros flag for day_of_week and hour_of_day
Added zeros to group_by_day without time zone
Added time zone support
Added zeros to group_by_second
Added zeros to group_by_hour
Fixed ruby 1.8
Added missing methods
Correctly exclude end
DRY tests
Order results for tests
Java hacks for return types
Made test helper methods easier to read
Added get the entire series to readme