Update strings.po

[geogiraux]

After a few days using the skin, I suggest a few improvements :

• change name from XBMC to Kodi (for the translated strings only)
• more consistent with the original (English) one : same formating for the add-on description, add missing item 31005, correct item 31010 (including the english word)
• revert/keep using the word playlist (which is shorter on screen and more consistent with others plugins)
• use a more consistent word for "item" (entrée), more convenient than the french translation of "object" or "title"

[chrisbevan]

Thanks!