Added functionality to check whether edge is internal

src/de/tudarmstadt/maki/simonstrator/api/component/vehicular/roadnetwork/RoadNetworkEdge.java

@@ -84,4 +84,8 @@ public class RoadNetworkEdge {
 	public String toString() {
 		return _edgeID;
 	}
+
+	public boolean isInternal() {
+		return _edgeID.startsWith(":");
+	}
 }