Terminology

We need to establish basic terminology for products and stages in the processing; the original ODD processing is rendered more confusing by the multiplicity of undefined and overlapping terms. These are some things we need terms for. Add more as necessary, and add suggestions.

• The original base ODD, which is normally p5subset.xml.
• A customization ODD, which is compiled/expanded/processed against a base ODD.
• Derivation is the process by which a customization ODD is compiled/expanded against a base ODD.
• The result of that derivation process (expanded ODD, or compiled ODD, in original terminology) is a derived ODD.
• The derived ODD (which should not have any references to any base ODDs via @source on *Spec elements) may be used as the base ODD for a chained derivation step.