Added a benchmark tool

Source/Problem4.cpp

@@ -35,7 +35,6 @@ int Problem4::START_NUM = 100;
 int Problem4::END_NUM = 999;
 
 Problem4::Problem4() : Problem("Find the largest palindrome made from the product of two 3-digit numbers."){
-
 }
 
 void Problem4::solve(){
@@ -102,3 +101,8 @@ uint64_t Problem4::getLargestPalindrome() const{
 	}
 	return *(palindromes.end() - 1);
 }
+
+void Problem4::reset(){
+	Problem::reset();
+	palindromes.clear();
+}