minor fixes in thesaurus_popup & authorities.pm

minor fixes in thesaurus_popup & authorities.pm
NEW plugin : the plugin that manages 60X field in UNIMARC (i think it's the same in marc21). Used to search a thesaurus entry & parse bibliothesaurus table for category NC (Common Name in french).
The user can enter a search term, and see entries corresponding. If the search is a real entry in the thesaurus, and this entry has dependencies, they are shown too.
For example, if the thesaurus contains :
Geo -- Europe -- France -- Marseille
Geo -- Europe -- France -- Paris
Hist -- Europe -- France -- Revolution

A search on "France"
shows
Geo --Europe --France and Hist -- Europe -- France on the left panel
When the user clic on Geo -- Europe -- France,
Marseille & Paris are shown on the right panel.

When the user selects a value, it's reported to the MARC editor.

NOTE : template ONLY IN FRENCH (but it's 11PM for instance, & i plan to go to bed :-) )