MI: really use MI names stored in history items

Solve 2 bugs : 
- history lib : display the multi name contained in the history item, instead of the one of the one actually set for the module instance.
- when rewind to a previous history item, rename the module instance whith the name stored in the history item.
All this because module instance name may change in time: for ex : when copy/paste an instance with a different name.

I think this is safe to merge (mainly cosmetic changes) but feel free to comment or delay after 1.6