Add tasks for all the new languages

Task/Polymorphic-copy/Sidef/polymorphic-copy.sidef

@@ -0,0 +1,22 @@
+class T(value) {
+    method display {
+        say value;
+    }
+}
+
+class S(value) < T {
+    method display {
+        say value;
+    }
+}
+
+var obj1 = T("T");
+var obj2 = S("S");
+var obj3 = obj2.dclone;         # make a deep clone of obj2
+
+obj1.value = "foo";             # change the value of obj1
+obj2.value = "bar";             # change the value of obj2
+
+obj1.display;                   # prints "foo"
+obj2.display;                   # prints "bar"
+obj3.display;                   # prints "S"