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Add empty book: When adding empty book records to the library, add an option to also create empty EPUB files. Useful if you intend to subsequently edit these files with the calibre editor. You can access the add empty books feature by right clicking the Add Book button.
Remove the need for -- when calling calibre-debug --diff
Prevent Content-Transfer-Enconding headers from confusing encoding detection in the diff tool
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Ignore the translations folder entirely since it is now version controlled in a separate github project.
Implement extraction of user manual strings for translation
Port compiling of .ui forms
Port imports
Port build script for building PyQt extensions to PyQt5
Port the progress indicator extension to PyQt5
Allow controlling PyQt5 import path via the env var PYQT5_IMPORT_PATH
faster builds
Get rid of the PyQt4 string from everywhere
Port: setMargin() reset() QStringList()

setMargin(): QLayout no longer has a setMargin() function, replace with
setContentsMargins()

reset(): QAbstractListModel no longer has reset(), replace with
beginResetModel(), endResetModel()

QStringList: No longer exists, a simply python list of strings works
instead
Fix mouse wheel not working in diff view
Port coffeescript compiler
Add note about headless Qt QPA plugin
Port WebKit imports and QChar

WebKit has been split up into QtWebKit and QtWebKitWidgets. Change
imports accordingly.

Replace use of QChar since it no longer exists in PyQt5
Port syntax highlighters