This switches our own `copypasta` crate with the more standardized
`clipboard` library, which allows us to get rid of the `xclip`
dependency on X11.
Additionally, this lays the foundation for native Wayland clipboard
support once the clipboard crate is updated (or a fork is created).
Fixes#5.
This adds the new Alacritty icon to the macOS binary available in the
github releases. On sizes 128x128 and up the image with scanlines is
included.
The ci deployment process should now also offer the svg file for
download so the .desktop file can be used without having to look through
the repos for the icon.
