update the lbfgs optimizer
update the unit tests for lbfgs
Added CPreprocessor::apply() method
fix a bug
Added CFeatures::copy_dimension_subset() method
Merge pull request #2337 from yorkerlin/develop

update the lbfgs optimizer
Merge pull request #2343 from lambday/feature/selection

Added CPreprocessor::apply() and CFeatures::copy_dimension_subset() methods
LDA.cpp eigennized
used decompositions for inverse claculations in CLDA.cpp
corrected ifdefs for eigen3
SVD method added
SVD method cleaned
enums added