Add tasks for all the new languages

Task/Higher-order-functions/Morfa/higher-order-functions.morfa

@@ -0,0 +1,12 @@
+func g(a: int, b: int, f: func(int,int): int): int
+{
+    return f(a, b);
+}
+
+import morfa.base;
+
+func main(): void
+{
+    println("Add: ", g(2, 3, func(a: int, b: int) { return a + b; }));
+    println("Multiply: ", g(2, 3, func(a: int, b: int) { return a * b; }));
+}