Allow timetable start dates to be set with full precision.

This avoids rounding of start dates when using minutes and
day length > 1.

src/base_consist.cpp

@@ -35,6 +35,7 @@ void BaseConsist::CopyConsistPropertiesFrom(const BaseConsist *src)
 	this->current_order_time = src->current_order_time;
 	this->lateness_counter = src->lateness_counter;
 	this->timetable_start = src->timetable_start;
+	this->timetable_start_subticks = src->timetable_start_subticks;
 
 	this->service_interval = src->service_interval;