Only storing primary features

src/feature_creation/feature_space/FeatureSpace.cpp

src/feature_creation/feature_space/FeatureSpace.hpp

src/feature_creation/node/FeatureNode.hpp

...re_creation/node/value_storage/nodes_value_containers.cpp

...re_creation/node/value_storage/nodes_value_containers.hpp

src/inputs/InputParser.cpp

src/inputs/InputParser.hpp