BlockingGraphRoadModel misses providing type

[hannesdm]

When running com.github.rinde.rinsim.examples.demo.factory.FactoryExample the following exception is thrown.

Exception in thread "main" java.lang.IllegalArgumentException: Could not resolve dependency for implementations of interface com.github.rinde.rinsim.core.model.road.GraphRoadModel, as requested by GraphRoadModelRenderer.builder().
	at com.google.common.base.Preconditions.checkArgument(Preconditions.java:146)
	at com.github.rinde.rinsim.core.model.DependencyResolver.constructDependencyGraph(DependencyResolver.java:90)
	at com.github.rinde.rinsim.core.model.DependencyResolver.resolve(DependencyResolver.java:115)
	at com.github.rinde.rinsim.core.model.ModelManager$Builder.build(ModelManager.java:268)
	at com.github.rinde.rinsim.core.Simulator.<init>(Simulator.java:88)
	at com.github.rinde.rinsim.core.Simulator$Builder.build(Simulator.java:347)
	at com.github.rinde.rinsim.examples.demo.factory.FactoryExample.run(FactoryExample.java:182)
	at com.github.rinde.rinsim.examples.demo.factory.FactoryExample.main(FactoryExample.java:96)

RinSim version: 4.3.0
A pull request has been created that allows BlockingGraphRoadModel to fullfill the dependency of a GraphRoadModel. #43
This fixes, among others, the FactoryExample.