* lock states: * open (everyone can do anything) * closed (with key can open and edit/change state) * view (everyone can open, with key can edit and change state) * copy book: * - when in view mode, copy books can be copied * - to create a copy book -> place book in shelf (written book name: 'nameOfBook<copy>'), set shelf to view mode. * then the book will be converted to a copy book. * - to remove copy function: rename book to 'nameOfBook<uncopy>' and set shelf mode to view * fixed some bugs
