Downloads the latest Canary build of Fluxer as a tarball and extracts it to
either /opt/fluxer (with symlink and desktop shortcut in /usr/local/bin/fluxer
and /usr/share/applications/fluxer-canary.desktop) or $HOME/.local.
I would have included a path for installing/updating Stable, but it appears Fluxer is pushing Canary builds even in Stable at the time of writing.