public class Debinarizer
Debinarizes a binary tree from the parser.
Node values with a '@' in them anywhere are assumed to be inserted
nodes for the purpose of binarization, and are removed.
The code also removes the last child of the root node, assuming
that it is an inserted dependency root.
Does whatever one needs to do to a particular tree.
This routine is passed a whole Tree, and could itself
work recursively, but the canonical usage is to invoke this method
via the Tree.transform() method, which will apply the
transformer in a bottom-up manner to each local Tree,
and hence the implementation of TreeTransformer should
merely examine and change a local (one-level) Tree.