* In the shell, the new command tt (to_trie) merges a list of trees into a
trie and prints it in a readable way, where unique subtrees are marked with
a "*" and alternative subtrees are marked with numbers.
* In the PGF web service, adding the parameter trie=yes to the parse and
translate commands augments the JSON output with a trie.
Example to try in the shell:
Phrasebook> p -lang=Eng "your son waits for you" | tt