(issue54) Implement a privilege drop to execute the program after installation. This commit is extremly ugly as I accidentally worked in a working tree that was partially merged with default. To review the real change please check the commit that will merge this branch into default.

.figure img {
    border: 1px solid lightgrey;
    margin-bottom: 10px;
    padding: 4px;
}
.figure .caption {
    margin-top: 0px;
    margin-bottom: 20px;
}