Added validation for the attribute "id" in the schemata; doing this needed
* xmlschemas.c: Added validation for the attribute "id" in the schemata; doing this needed error report fixes for notations, facets and group. Changed NOTATION validation to work with the declared NOTATIONs in the schema; this does have no impact on the validation via the relaxng module. * xmlschemastypes.c include/libxml/xmlschemastypes.h: Added xmlSchemaNewNOTATIONValue to the API to be able to do the NOTATION validation described above. * test/schemas/element-err_0.xsd test/schemas/annot-err_0.xsd: Fixed the values of the "id" attributes, which were not validated previously.