use slice of Time struct for timetable instead of [][]int.
use slice of Time struct for timetable instead of [][]int.

it is easy to get these things if it is fomred single dimentioned array.
- first bus of the day
- last bus of the day
- get time of next bus by specified time
please note that the array is needed to be sorted by time in ascending
order.

sassy/KeiseiBusTime,pankona/KeiseiBusTime