Add tasks for all the new languages

Task/Sierpinski-triangle/Swift/sierpinski-triangle.swift

@@ -0,0 +1,44 @@
+import Foundation
+
+// Easy get/set of charAt
+extension String {
+    subscript(index:Int) -> String {
+        get {
+            var array = Array(self)
+            var charAtIndex = array[index]
+            return String(charAtIndex)
+        }
+
+        set(newValue) {
+            var asChar = Character(newValue)
+            var array = Array(self)
+            array[index] = asChar
+            self = String(array)
+        }
+    }
+}
+
+func triangle(var n:Int) {
+    n = 1 << n
+    var line = ""
+    var t = ""
+    var u = ""
+
+    for (var i = 0; i <= 2 * n; i++) {
+        line += " "
+    }
+
+    line[n] = "*"
+
+    for (var i = 0; i < n; i++) {
+        println(line)
+        u = "*"
+        for (var j = n - i; j < n + i + 1; j++) {
+            t = line[j-1] == line[j + 1] ? " " : "*"
+            line[j - 1] = u
+            u = t
+        }
+        line[n + i] = t
+        line[n + i + 1] = "*"
+    }
+}