Added a benchmark tool

Source/Problem15.cpp

@@ -52,7 +52,6 @@ void Problem15::move(int currentX, int currentY, uint64_t& numOfRoutes){
 }
 
 Problem15::Problem15() : Problem("How many routes from the top left corner to the bottom right corner are there through a 20×20 grid if you can only move right and down?"), numOfRoutes(0){
-
 }
 
 void Problem15::solve(){
@@ -97,3 +96,8 @@ uint64_t Problem15::getNumberOfRoutes() const{
 	}
 	return numOfRoutes;
 }
+
+void Problem15::reset(){
+	Problem::reset();
+	numOfRoutes = 0;
+}