Added META-INF generation, and refactored mimetype handling for OPF and NCX.
Added META-INF generation, and refactored mimetype handling for OPF and NCX.

gitenberg-dev/HTMLBook,wastemobile/HTMLBook,gitenberg-dev/HTMLBook,oreillymedia/HTMLBook,oreillymedia/HTMLBook,mushroomgithub/HTMLBook,wastemobile/HTMLBook,mushroomgithub/HTMLBook,gitenberg-dev/HTMLBook,oreillymedia/HTMLBook,macmillanpublishers/HTMLBook,mushroomgithub/HTMLBook,macmillanpublishers/HTMLBook,macmillanpublishers/HTMLBook