Assertion triggered using Naive Bayes

Hey Future Computing,

I got a problem running your Naive Bayes GPU implementation. I set up your project like described and ran inside the test folder the following command:
```
build/test-classification --gpu --loglevel 4 --dataset data/iris.txt --type csv --clas bayes
```

It fails at /src/mlearn/math/matrix_utils.cu:378 with j=6 and X.cols = 120.

Any help would be appreciated!