Prune an ADDTREE tree in Node format using data.tree
prune.addtree(addtree, prune.empty.leaves = TRUE,
remove.bad.parents = TRUE, verbose = TRUE)
rtMod trained with s.ADDTREE
Logical: If TRUE, remove leaves with 0 cases. Default = TRUE
Logical: If TRUE, remove nodes with no siblings but children and give their children to their parent. Default = TRUE