Add ppi (pixels per inch) to BookReader metadata API
Add ppi (pixels per inch) to BookReader metadata API

internetarchive/bookreader,yankl/bookreader,Islandora/internet_archive_bookreader,niksu/bookreader,internetarchive/bookreader,garyrh/bookreader,niksu/bookreader,garyrh/bookreader,yankl/bookreader,yankl/bookreader,nikolas/bookreader,brisandbeans/bookreader,niksu/bookreader,brisandbeans/bookreader,brisandbeans/bookreader,yankl/bookreader,openlibrary/bookreader,Islandora/internet_archive_bookreader,garyrh/bookreader,openlibrary/bookreader,Islandora/internet_archive_bookreader,niksu/bookreader,brisandbeans/bookreader,openlibrary/bookreader,garyrh/bookreader,openlibrary/bookreader,openlibrary/bookreader,garyrh/bookreader,brisandbeans/bookreader,nikolas/bookreader,Islandora/internet_archive_bookreader,yankl/bookreader,niksu/bookreader,Islandora/internet_archive_bookreader