Add item name in persistence's item list

If the item name is available add it to the list entry.
If you use a lot of sensors, that are grouped differently in the sitemap, it is a (IMHO) common case to use "temperature" as text for all temperature sensor.
If you would like to use the persistence graph of HABmin to draw a graph of one or more items (e.g. temperature sensors) the item text is perhaps not enough to identify the correct item.