We sent an order to the client for action and xxx2Many so its screen has
always a default order set.
To position a new record on non editable tree, we use the order of the 'id'
column if presents.
issue8880
review276501003
We convert all the fields that were storing python code into PYSON.
We add a pyson attribute on field tag to store PYSON value.
issue4416
review6971002