I was able to install Mediaelch in Ubuntu 15.04 (Vivid) using the source for 14.04.
Method: 1 Adding Repository and Signing Key
Turns out adding a repo and its key manually is no big deal. Create a file, add the info from Launchpad, add the key, update and install:
sudo sh -c 'printf "deb http://ppa.launchpad.net/kvibes/mediaelch/ubuntu trusty main\n deb-src http://ppa.launchpad.net/kvibes/mediaelch/ubuntu trusty main\n" > /etc/apt/sources.list.d/kvibes-mediaelch-ubuntu-trusty.list'
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 00DAEE81 && echo That worked. || echo That totally failed.
sudo apt-get update && sudo apt-get install mediaelch
Not so hard afterall.
Method: 2 Add New Repo and Edit for Older Source
Don't know anything about manually adding repos and signing keys, so I just added the repository according to instructions and merely replaced "vivid" with "trusty" in its list file. I didn't bother renaming the .list file.
sudo apt-add-repository ppa:kvibes/mediaelch
sudo sh -c 'sed -i "s/vivid/trusty/g" /etc/apt/sources.list.d/kvibes-ubuntu-mediaelch-vivid.list'
Then just update and install
sudo apt-get update && sudo apt-get install mediaelch
Worked a charm.