Add tasks for all the new languages

Task/Semiprime/Swift/semiprime.swift

@@ -0,0 +1,37 @@
+import Foundation
+
+func primes(n: Int) -> AnyGenerator<Int> {
+
+  var (seive, i) = ([Int](0..<n), 1)
+  let lim = Int(sqrt(Double(n)))
+
+  return anyGenerator {
+    while ++i < n {
+      if seive[i] != 0 {
+        if i <= lim {
+          for notPrime in stride(from: i*i, to: n, by: i) {
+            seive[notPrime] = 0
+          }
+        }
+        return i
+      }
+    }
+    return nil
+  }
+}
+
+func isSemiPrime(n: Int) -> Bool {
+  let g = primes(n)
+  while let first = g.next() {
+    if n % first == 0 {
+      if first * first == n {
+        return true
+      } else {
+        while let second = g.next() {
+          if first * second == n { return true }
+        }
+      }
+    }
+  }
+  return false
+}