Add tasks for all the new languages

Task/Repeat-a-string/Swift/repeat-a-string-1.swift

@@ -0,0 +1,19 @@
+extension String {
+  // Slower version
+  func repeatString(n: Int) -> String {
+    return Array(count: n, repeatedValue: self).joinWithSeparator("")
+  }
+
+  // Faster version
+  // benchmarked with a 1000 characters and 100 repeats the fast version is approx 500 000 times faster :-)
+  func repeatString2(n:Int) -> String {
+    var result = self
+    for _ in 1 ..< n {
+      result.appendContentsOf(self)   // Note that String.appendContentsOf is up to 10 times faster than "result += self"
+    }
+    return result
+  }
+}
+
+print( "ha".repeatString(5) )
+print( "he".repeatString2(5) )

Task/Repeat-a-string/Swift/repeat-a-string-2.swift

@@ -0,0 +1 @@
+String(count:5, repeatedValue:"*" as Character)

Task/Repeat-a-string/Swift/repeat-a-string-3.swift

@@ -0,0 +1,19 @@
+extension String {
+  func repeatBiterative(count: Int) -> String {
+        var reduceCount = count
+        var result = ""
+        var doubled = self
+        while reduceCount != 0 {
+            if reduceCount & 1 == 1 {
+                result.appendContentsOf(doubled)
+            }
+            reduceCount >>= 1
+            if reduceCount != 0 {
+                doubled.appendContentsOf(doubled)
+            }
+        }
+        return result
+    }
+}
+
+"He".repeatBiterative(5)