Regarding this class as well as CTreeMachine being templated. Will these classes be visible from SWIG interfaces? If yes, then I think we should be careful how we handle it and use the same pattern we have for other templated classes in Shogun like DenseFeatures. If not, then it is fine to do it this way but I would mark it somehow in the name of the class; e.g. TreeMachineImpl or so.

Any thoughs on this @vigsterkr, @karlnapf?