v0.0.8-alpha.1

1. Added support for sandbox data cleanup.
2. Added support for web page data cleanup.
3. The homepage layout is now more centered and adapts to wider screens.
4. Most pop-ups can now be closed using the escape key.
5. Added several new themes, and the theme switcher has a new design.
6. Added support for high-resolution screens on Windows.
7. The layout system is now easier to use.