2007/12/21 12:28:07 mst 1.12.82.1: refactoring for XDocumentProperties import/export: chart
- xmloff/source/chart/SchXML{Export,Import}.cxx,
  xmloff/source/chart/contexts.{hxx,cxx}:
  + SchXMLDocContext virtually inherits from SvXMLImportContext
  + new class SchXMLFlatDocContext_Impl for flat file ODF;
    multiply inherits from SchXMLDocContext and SvXMLMetaDocumentContext
  + refactor SchXMLImport::CreateContext to use SvXMLMetaDocumentContext