Add tasks for all the new languages

Task/Mutual-recursion/Ring/mutual-recursion.ring

@@ -0,0 +1,19 @@
+see "F sequence : "
+for i = 0 to 20
+    see "" + f(i) + " "
+next
+see nl
+see "M sequence : "
+for i = 0 to 20
+    see "" + m(i) + " "
+next
+
+func f n
+     fr = 1
+     if n != 0 fr = n - m(f(n - 1)) ok
+     return fr
+
+func m n
+     mr = 0
+     if n != 0 mr = n - f(m(n - 1)) ok
+     return mr