[FIX] Tree: Reintroduce preprocessors.#2566

Merged

janezd merged 2 commits intobiolab:masterfrom

Sep 14, 2017

Commits on Sep 8, 2017

Explicitly add preprocessors to the list of parameters in the constructor.
thocevar
committed

Commits on Sep 13, 2017

Add test
astaric
committed