Update legal styles for Civil Law cases rendering

New code: no ```title``` = civil law case with title in ```short-title```.
It contains backward compatibility code for items already recorded with a "ghost" ```author``` (former hook to know if it's a civil law case in Zotero, and still used in other softwares.)
Well, I don't think we did discuss this...

The "note" field is used to add some infos the users may want to display. It's not mandatory (It's really to provide some extra infos.)

It may not be mapped in other software than Zotero, but it doesn't break the style for others. Users are using lluelles.csl and mcgill-fr.csl with Papers, and no pbs were reported.