SCE — Refences to non-existing specifications

For context, SCE contains references to KPMN & PPMN as standards that had planed to use SCE. However, the KPMN Finalization Task Force decided not to finish their specification and did not submit an FTF report. As a result, KPMN is not a viable specification for SCE to reference. PPMN has yet to be finalized and although its Finalization Task Force is active, it is not far enough along to be sure that it will pass all checks & votes in time and be adopted.

Remove references to non-existing specifications

Remove all references to KPMN and PPMN.

The removal of these references has no effect on SCE as a language because they have only served to provide context.

A later RTF may reintroduce these references, when the other specifications have actually been adopted.