add confusion_matrix output and print classification report

@zhyongquan  please involve me in the project, I'd like to contribute my effort to translate some chapters.

Code/Day 11_k-NN.py

@@ -28,4 +28,7 @@ y_pred = classifier.predict(X_test)
 
 # Making the Confusion Matrix
 from sklearn.metrics import confusion_matrix
+from sklearn.metrics import classification_report
 cm = confusion_matrix(y_test, y_pred)
+print(cm)
+print(classification_report(y_test, y_pred))