adjust the API for model selection
Added HierarchicalMultilabelModel class
names of files changed
modular interface added
kde notebook added
Effects of h and num_samples added;comments addressed
Merge pull request #2429 from mazumdarparijat/pca

paths to files changed
add bounding method in factor graph model for submodularity
Fix few typos in MMD notebook.
Guard LDA in GUIClassifier against missing Eigen.
Merge pull request #2411 from yorkerlin/develop

adjust the API of KL methods for model selection
Merge pull request #2433 from iglesias/notebook/mmd_fixes

Fix few typos in MMD notebook.
improve the  performance of softmax
Merge pull request #2434 from iglesias/fix/GUIClassifier

Guard LDA in GUIClassifier against missing Eigen.
Merge pull request #2435 from yorkerlin/develop

improve the  performance of softmax
Merge pull request #2427 from mazumdarparijat/kdensity

Kernel density estimation
Use the correct guard (HAVE_EIGEN3 instead of HAVE_EIGEN) in GUIClassifier. This fixes broken test in cmdline static.
Merge pull request #2385 from Jiaolong/graph_cut_mosek

add bounding method in factor graph model for submodularity
Modified HierarchicalMultilabelModel:
    * Changed get_attr_vector -> get_label_vector
    * Minor refactorings in tests and source code
Merge pull request #2436 from iglesias/fix/cmdline_static_classifier_lda_test

Use the correct guard (HAVE_EIGEN3 instead of HAVE_EIGEN)