Add tasks for all the new languages

Task/Pangram-checker/Swift/pangram-checker-1.swift

@@ -0,0 +1,16 @@
+import Foundation
+
+let str = "the quick brown fox jumps over the lazy dog"
+
+func isPangram(str:String) -> Bool {
+    let stringArray = Array(str.lowercaseString)
+    for char in "abcdefghijklmnopqrstuvwxyz" {
+        if (find(stringArray, char) == nil) {
+            return false
+        }
+    }
+    return true
+}
+
+isPangram(str) // True
+isPangram("Test string") // False

Task/Pangram-checker/Swift/pangram-checker-2.swift

@@ -0,0 +1,4 @@
+func isPangram(str: String) -> Bool {
+  let (char, alph) = (Set(str.characters), "abcdefghijklmnopqrstuvwxyz".characters)
+  return !alph.contains {!char.contains($0)}
+}