Simply/Optimize eval_sliced_Transform for the CPU case.

src/faust_linear_operator/CPU/faust_Transform.hpp

src/faust_linear_operator/CPU/faust_TransformHelper.h

src/faust_linear_operator/CPU/faust_TransformHelper.hpp

src/faust_linear_operator/faust_TransformHelperGen.h

src/faust_linear_operator/faust_TransformHelperGen.hpp