Please add an example for StochasticGradientDescent Class.

Also examples for the online training of SVMs, answering the question about incremental training in https://stackoverflow.com/questions/43555950/accord-net-svm-incremental-training

Help Topic: http://accord-framework.net/docs/html/T_Accord_MachineLearning_VectorMachines_Learning_StochasticGradientDescent.htm