reporting the problem)
code cleanup in goto_day() and update_cal_panel()
static variables today and slctd_day added
calendar_store_current_date(), calendar_get_slctd_day(),
calendar_get_slctd_day_sec(), calendar_init_slctd_day() created
calendar_move_up(), calendar_move_down(), calendar_move_left() and
calendar_move_right() created
calendar_set_first_day_of_week(), calendar_change_first_day_of_week() and
calendar_week_begins_on_monday() created
