almost finish CKGroup

LibCmo/CK2/CKDefines.hpp

@@ -34,6 +34,7 @@ namespace LibCmo::CK2 {
 	//using CKClassDependenciesCountFct = std::function<CKINT(CKINT)>;
 
 	struct CKClassDesc {
+		bool IsValid; /**< True if this CKClassDesc is a valid one. Because CK_CLASSID may not be consecutive. */
 		bool Done;
 		// Initialized upon class registration
 		CK_CLASSID Self;
@@ -62,6 +63,7 @@ namespace LibCmo::CK2 {
 		//XContainer::XSArray<CK_CLASSID> ToNotify; // List of ClassID to notify when an object of this class is deleted (inverse of ToBeNotify) 					
 
 		CKClassDesc() :
+			IsValid(false),
 			Done(false),
 			Self(CK_CLASSID::CKCID_OBJECT), Parent(CK_CLASSID::CKCID_OBJECT),
 			CreationFct(nullptr), ReleaseFct(nullptr), NameFct(nullptr),