(issue38) Add long time error handling. A Long Time Error is an error that will be shown to the user if it happened at least seven times with an interval of at least a day between occurances. After one success a long time error will be reset.

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