graphQL/graphQL: Correction of a bug in func (ts *typeSystem) validateValueIV.
graphQL/wrapTool: new file with functions Wrap and Unwrap.
graphQL/write: ObjectValue -> objectValue (no more exported); functions GetTypeString, GetTypeFlatString, WriteType and WriteTypeFlat added.
misc: new type 'Nerror', which embeds 'error' and adds an error number.