Built generic multiclass learning framework

by pluskid for Shogun Machine Learning Toolbox

I'm a student with strong machine learning and open source programming experiences. I'm applying for a project that will implement a generic multiclass learning framework in shogun. While shogun is the state-of-the-art toolbox for binary classifiers, more multiclass methods need to be added to make it competitive in this area. Many real-world problems are naturally multiclass. So adding strong multiclass support for shogun would benefits a large community.