Add tasks for all the new languages

Task/Polymorphic-copy/Swift/polymorphic-copy.swift

@@ -0,0 +1,24 @@
+class T {
+  required init() { } // constructor used in polymorphic initialization must be "required"
+  func identify() {
+    println("I am a genuine T")
+  }
+  func copy() -> T {
+    let newObj : T = self.dynamicType() // call an appropriate constructor here
+    // then copy data into newObj as appropriate here
+    // make sure to use "self.dynamicType(...)" and
+    // not "T(...)" to make it polymorphic
+    return newObj
+  }
+}
+
+class S : T {
+  override func identify()  {
+    println("I am an S")
+  }
+}
+
+let original : T = S()
+let another : T = original.copy()
+println(original === another) // prints "false" (i.e. they are different objects)
+another.identify() // prints "I am an S"