Add tasks for all the new languages

Task/Factorial/SequenceL/factorial-1.sequencel

@@ -0,0 +1 @@
+factorial(n) := product(1 ... n);

Task/Factorial/SequenceL/factorial-2.sequencel

@@ -0,0 +1 @@
+factorials(n)[i] := product(1 ... i) foreach i within 1 ... n;

Task/Factorial/SequenceL/factorial-3.sequencel

@@ -0,0 +1,5 @@
+factorial: int -> int;
+factorial(n) :=
+		1 when n <= 0
+	else
+		n * factorial(n-1);

Task/Factorial/SequenceL/factorial-4.sequencel

@@ -0,0 +1,7 @@
+factorial(n) :=
+	factorialHelper(1, n);
+	
+factorialHelper(acc, n) :=
+		acc when n <= 0
+	else
+		factorialHelper(acc * n, n-1);