$ apt-get update
[...]
Err http://ppa.launchpad.net trusty/main i386 Packages
  404  Not Found
[...]
W: Failed to fetch http://ppa.launchpad.net/clicompanion-devs/clicompanion-nightlies/ubuntu/dists/trusty/main/binary-i386/Packages 404  Not Found

E: Some index files failed to download. They have been ignored, or old ones used instead.