Add tasks for all the new languages

Task/Factorial/Ceylon/factorial.ceylon

@@ -0,0 +1,20 @@
+shared void run() {
+	
+	Integer? recursiveFactorial(Integer n) =>
+			switch(n <=> 0)
+			case(smaller) null
+			case(equal) 1
+			case(larger) if(exists f = recursiveFactorial(n - 1)) then n * f else null;
+	
+	
+	Integer? iterativeFactorial(Integer n) =>
+			switch(n <=> 0)
+			case(smaller) null
+			case(equal) 1
+			case(larger) (1:n).reduce(times);
+	
+	for(Integer i in 0..10) {
+		print("the iterative factorial of     ``i`` is ``iterativeFactorial(i) else "negative"``
+		       and the recursive factorial of ``i`` is ``recursiveFactorial(i) else "negative"``\n");
+	}
+}