Changes:
- Added support for opening HTML files (#641)
- Consistent inner and outer margins (#255)
- The automatic layout no longer supports 4 columns (58d5e50)
- Fixed long words overflowing (#654)
- Fixed custom themes not saved across sessions (#660)
- Fixed shortcuts for key pads (#677)
- Fixed opening non-UTF-8 zipped FB2 files (#629)
- Fixed books not opening on GNOME 40 (#689)