Bug solved in ankus-core when the input is not in tabular format

Hello, I am Jesús Morán

The progam has a bug when delimiter is not tab

For example, if the input dataset is formed by:
Richard,Spiderman,5
Richard,Batman,1
Richard,IronMan,4
Mary,Batman,2
Mary,IronMan,5
Steve,Spiderman,4
Steve,Batman,3
Steve,IronMan,2

And the similarity is formed by:
Mary,Richard
Mary,Steve

The program crash:

![crash](https://cloud.githubusercontent.com/assets/7209542/4677685/4916ea8e-55eb-11e4-9534-7d22b20fd601.png)

With the changes the program apparently run correctly, and the obtained output is:
Mary Spiderman 4.5

Regards