Usage Example::
        
            >>> timewrapper.day_interval(2014, 12)
            (datetime(2014, 12, 1, 0, 0, 0), datetime(2014, 12, 31, 23, 59, 59))

def month_interval(year, month, return_str=False):
        """
        
        Usage Example::
        
            >>> timewrapper.day_interval(2014, 12)
            (datetime(2014, 12, 1, 0, 0, 0), datetime(2014, 12, 31, 23, 59, 59))
        """
        if month == 12:
            start, end = datetime(year, month, 1), datetime(year+1, 1, 1) - timedelta(seconds=1)
        else:
            start, end = datetime(year, month, 1), datetime(year, month+1, 1) - timedelta(seconds=1)
            
        if not return_str:
            return start, end
        else:
            return str(start), str(end)