Added an operation isDependent in Parameter.
Modified method getParameterNamed in PiGraph to getParameterNamedWithParent, preventing from mixing parameters with the same name at different hierarchy levels.
Modified the way to handle parameter values in the Scenario:
-classification STATIC/DEPENDENT/DYNAMIC is now INDEPENDENT/ACTOR_DEPENDENT/PARAMETER_DEPENDENT;
-when no value is found for an independent parameter in the scenario, we try to parse the expression of the parameter to get an int value;
-configuration interfaces are no more added to the scenario editor
ParameterValue now only keeps value under the form of Strings