apply_to_feature_matrix method fixed in PCA
PCA unit test added
PCA code changes fixed
PCA in-place
updating revision of data submodule
data submodule update
data state updated after merge
PCA unittest added/PCA code minor changes
PCA unit-test divided into small parts
minor corrections in comments
proper error messages
some modifications to  make this at least compile.
added mkl grid search example (which doesnt work)
Merge pull request #1885 from karlnapf/develop

modelselection_grid_search_mkl
added PCA in-place as well as reallocate
PCA init fixed
SG_ADD corrected for mem_mode
Merge pull request #1874 from mazumdarparijat/pca

PCA bug fixed
fix mistake in ssk kernel example
fix uninitialized memory bug in Parameter::copy