filter options in add menu of book picker
Merge branch 'master' into 57577828

Conflicts:
	scripts/gh-book/gh-book.less
can now add a book to an epub
Merge remote-tracking branch 'origin/master' into 57577828
make epub container not dirty on load
Merge remote-tracking branch 'origin/master' into 57577828
simplify adding things to opf manifest
move default opf and nav files into templates
set things allowed to be added to books based on the EpubContainer type for gh-book
move gh-book default opf and nav files into a gh-book scoped directory
ignore epubContainer in allContent, use 'singleton' one instead
Merge pull request #70 from oerpub/57577828

add new books