[WIP] Add svdd implementation

Added realization of support vector data description from http://www.csie.ntu.edu.tw/~cjlin/libsvmtools/
Less maths and more intuition please: why is this useful? Why is it more/differently useful than a standard SVM? What's the intuition behind it.

We also need a figure, generated from the example (don't check the generated figure in the git, use the fact that it is automatically generated by 'make html').