[FLINK-1429] [streaming] Scala programming guide update: intro & operators, minor fixes

This closes #463

docs/programming_guide.md

@@ -58,7 +58,7 @@ public class WordCountExample {
     public static void main(String[] args) throws Exception {
         final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
 
-	    DataSet<String> text = env.fromElements(
+        DataSet<String> text = env.fromElements(
             "Who's there?",
             "I think I hear them. Stand, ho! Who's there?");
 

flink-staging/flink-streaming/flink-streaming-scala/src/main/scala/org/apache/flink/streaming/api/scala/DataStream.scala

@@ -221,8 +221,8 @@ class DataStream[T](javaStream: JavaStream[T]) {
    *
    *
    */
-  def iterate[R](maxWaitTimeMillis:Long = 0)(stepFunction: DataStream[T] => (DataStream[T], DataStream[R]))
-        : DataStream[R] = {
+  def iterate[R](maxWaitTimeMillis:Long = 0)
+                (stepFunction: DataStream[T] => (DataStream[T], DataStream[R])) : DataStream[R] = {
     val iterativeStream = javaStream.iterate(maxWaitTimeMillis)
 
     val (feedback, output) = stepFunction(new DataStream[T](iterativeStream))
@@ -495,23 +495,6 @@ class DataStream[T](javaStream: JavaStream[T]) {
    */
   def split(selector: OutputSelector[T]): SplitDataStream[T] = javaStream.split(selector)
 
-//  /**
-//   * Creates a new SplitDataStream that contains only the elements satisfying the
-//   *  given output selector predicate.
-//   */
-//  def split(fun: T => String): SplitDataStream[T] = {
-//    if (fun == null) {
-//      throw new NullPointerException("OutputSelector must not be null.")
-//    }
-//    val selector = new OutputSelector[T] {
-//      val cleanFun = clean(fun)
-//      def select(in: T): java.lang.Iterable[String] = {
-//        List(cleanFun(in))
-//      }
-//    }
-//    split(selector)
-//  }
-
   /**
    * Creates a new SplitDataStream that contains only the elements satisfying the
    *  given output selector predicate.