Delivery-Points dependant on specific depot

[graphhopper]

Delivery-Points dependant on specific depot

This is basically a pickup and delivery problem, a whole new and very interesting problem dimension. I made two things: First, I clarified again what jsprit's capabilities are. The readme may have been kind of misleading. Second, I put it on my implementation agenda, i.e. I am going to implement it. But I can hardly estimate how long this will take or to put it in other words, I do not want to set myself a deadline.

Enroute pickups and deliveries problems can now be solved. Look at the following examples to see how they can be implemented:

https://github.com/jsprit/jsprit/blob/master/jsprit-examples/src/main/java/jsprit/examples/SimpleEnRoutePickupAndDeliveryExample.java

https://github.com/jsprit/jsprit/blob/master/jsprit-examples/src/main/java/jsprit/examples/SimpleEnRoutePickupAndDeliveryWithDepotBoundedDeliveriesExample.java