Added IndexOf support for List.

tests/ListTests.cpp

@@ -60,6 +60,15 @@ TEST_CASE("Create list of bools, assign to it", "[Utilities]") {
     CHECK(ls[1]);
 }
 
+TEST_CASE("Test IndexOf", "[Utilities]") {
+    auto ls = List<int>({5, 200, 1500, -500, 5, 300, -500});
+    CHECK(ls.IndexOf(5) == 0);
+    CHECK(ls.IndexOf(1500) == 2);
+    CHECK(ls.IndexOf(300) == 5);
+    CHECK(ls.IndexOf(684) == -1);
+}
+
+
 
 
 #endif