Spam Detection -Add comment while downloading data (#261)

* Added  code to classify github issues into the best 3 labels.
1.Created a class to hold Prediction values
2.Added Score filed in GitHubIssuePrediction class.
3.Changed the existing code in Labeler class.
4.Added new method to find the best 3 scores and return their indexes so that we can get the labels of those matched indexes from slotnames.

* Added comment while downlaoding the data so that the developers are aware of the third party terms when using data to train/test

samples/csharp/getting-started/BinaryClassification_SpamDetection/SpamDetectionConsoleApp/Program.cs

@@ -24,6 +24,8 @@ static void Main(string[] args)
             {
                 using (var client = new WebClient())
                 {
+                    //The code below will download a dataset from a third-party, UCI (link), and may be governed by separate third-party terms. 
+                    //By proceeding, you agree to those separate terms.
                     client.DownloadFile("https://archive.ics.uci.edu/ml/machine-learning-databases/00228/smsspamcollection.zip", "spam.zip");
                 }