CLaplacianInferenceMethodWithLBFGS  preview

Just for previewing the code. 
The original Newton method used in CLaplacianInferenceMethod class is replaced by the L-BFGS method using the provided ShoGun API in the CLaplacianInferenceMethodWithLBFGS class.
In order to do so, I change the private data members in CLaplacianInferenceMethod to be protected. 
If I am not allowed to do that, please let me know.
The class correctly works on the fm dataset (fm_test_real.dat  fm_train_real.dat  label_train_twoclass.dat) in classifier_gaussian_process_binary_classification
I will test the code thoroughly and go for the next task (https://github.com/shogun-toolbox/shogun/issues/1971) suggested by Emt.
It is possible that my coding style is not consistent with the ShoGun coding style. 
Please let me know the specific coding style so that I can set it in VIM.