add pickup and delivery
intro pickup and delivery
Merge branch 'master' into vrpWithBackhauls

Conflicts:
	jsprit-examples/src/main/java/examples/SolomonExample.java
add test
introduce Pickup and Delivery, and adjust tests
remove unused classes
improve solutionPlotter - add size-label and mark first tourAct
adjust tests to changes in branch
create new plotter - with more options compared to static
solutionPlotter
create new services and serviceActivities, i.e. pickup and delivery as
well as their corresponding activities
adjustments to introducing pickup and delivery
add new test-resource for building pdVRP from scratch
no change
add some default hard constraints
fix bug in CalculatesServiceInsertion
refinements to incorporate pickup and deliveries
improve updates/updaters at act- and routeLevel
add files for examples
add precondition to service: capacity-demand must be greater than or
equal to zero
add problemConstraints