Revised definition for Classifier_Matching_Rule and Classifier_Substitution_Rule

[jjhugues]

After discussion on matching rules, the following must be updated:

• [X] The definition of Classifier_Matching_Rule and Classifier_Substitution_Rule in Modeling_Properties should define the default value specified in the document
• [X] Classifier_Substitution_Rule should be Type_Extension by default, this makes sense for refinements.
• [x] In the case of subprogram access connections, Classifier_Match is too restrictive. We need an equivalent of Signature_Match. Suggestion is to call is Same_Signature

[jjhugues]

All points have been recorded in the core document.