provide a backward compatibility with review-epubmaker legacy.
colophon uses a value of 'rights' parameter.
'coverfile' produces cover file <bookname>-cover.html with common header/footer. (legacy. should use 'cover')
'titlepagefile' produces title file <bookname>-title.html with common header/footer. (legacy. should use 'titlefile')
change the content value of generator in meta element to 'Re:VIEW'.