add default methods to pruning interface

contribs/informed-mode-choice/src/main/java/org/matsim/modechoice/pruning/CandidatePruner.java

@@ -37,13 +37,17 @@ default void onSelectCandidate(PlanModel model, PlanCandidate candidate) {
 	 *
 	 * @return positive threshold, if negative it will not be applied
 	 */
-	double planThreshold(PlanModel planModel);
+	default double planThreshold(PlanModel planModel) {
+		return -1;
+	}
 
 
 	/**
 	 * Calculate threshold to be applied on a single trip. Modes worse than this threshold on this trip will be discarded.
 	 *
 	 * @return positive threshold, if negative it will not be applied
 	 */
-	double tripThreshold(PlanModel planModel, int idx);
+	default double tripThreshold(PlanModel planModel, int idx) {
+		return -1;
+	}
 }