bin: add animecheck script
systemd: make dropbox work without xorg

If environment variable DISPLAY is set dropbox will expect that Xorg is
running and won't start properly.
systemd: improve tmux service
systemd: improve gpg-agent
systemd: improve offlineimap
systemd: nicer descriptions
systemd: imporve pulseaudio
systemd: add console target
systemd: improve x services