within a single document for multi-HTML rendering, add section prefix in generated file names
within a single document for multi-HTML rendering, add section prefix in generated file names

svn: r15693

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket