Behaviour arguments referencing

[sylvain-openflexo]

Referencing a behaviour argument in the control graph of a behaviour today requires "parameters.arg" syntax. This has been analyzed as a bad practice and should be refactored ("arg" syntax will be easier to understand and more classical).
This should be done in 2.99 version in order to get the opportunity to migrate XML models to this new syntax.
This requires that "arg = parameters.arg" statements must be transformed to "this.arg = arg" for example.