Waypaper

New in this release
- Caching of wallpapers in the folders makes loading almost instant (after the first time)
- Improved caching indicator
- Improved interface response while loading

New in this release

- Setting background color
- Improved handling of installed backends
- Improved user arguments handling


New in this release

- Support for various backends like swww, swaybg and even feh (for x11)
- Adding user arguments --backend and --fill
- Minor improvements

First stable release

New from initial release:
- Ability to scan subfolders (up to 2 levels)
- Ability to select fill type
- Reworked architecture