statistic helper classes

test-cases
modified grid importance for better trap-detection

math/DrawList.h

@@ -91,6 +91,15 @@ public:
 	}
 
 	/** get a random element based on its probability */
+	T get() {
+		double tmp;			// ignored
+		return get(tmp);
+	}
+
+	/**
+	 * get a random element based on its probability.
+	 * the probability of the picked element is returned using the out parameter
+	 */
 	T get(double& elemProbability) {
 
 		// generate random number between [0:cumProbability]