added ' ' from template to javascript so it can be used for portable version too.
added get_cover, get_opf, portable_cover, portable_opf to libraries.js and library.html for future mocks
added/prepared string-parts-tmpl in library.html and libraries.js for portable
Memoryoftheworld backed on master. Merge branch 'master' of github.com:marcellmars/letssharebooks