Changed the External system to match up with the system discused:
 - 	Trailer Class now requires an estimated arrival time and date.
 -	Hardcoded Trailers are set to arrive Jan 1, 2013 at different times
 -	New created trailers can still choose to arrive any other date.
 - 	For now, all new orders are forced to be delivered Jan 1, 2013.
 -	ProductType Class now contains a new field: minuteToKiloRatio.
 -	SubOrders estimated weight are now calculated based on its weight
	and its product type.
 -	Few bugfixes