let's standardize!

A first way to produce a standardized tree from triples.

`treeTranslation.py` contains the algo. I think some code could be factorized (but i have errors whenever i try something)

If you want to try it: 
  - run `demo6.py` (in /demo folder)
  - enter your question

If someone is comfortable with the filling of `requesthandler.py ` (and the other parts to communicate with external modules), please do it :)