Changes in featConverter.py

Hey,

I am using this project to implement SVM on Android for my thesis project. I found few typo mistakes in the instructions and changed them. Later I found out that predict_label() required Xte.libsvm file but it is different to test_label.libsvm because it's not a product of two files. Xte.libsvm is just transformation of Xte.csv file but the file requires Y_file to be mentioned. So I have implemented a way in which I can just mention "blank" instead of file name of Y_file and it will generate Xte.libsvm like it should be. I have just copied the function and overloaded that.

It is my first pull request to any open source project so kindly ignore any discrepancies and do give feedback if there's any suggestion. 

Regards,

Wahib