Compatibility with Piwigo 12

compatible with Piwigo 2.7

New languages:
* Norwegian (Norsk bokmål [NO]), thanks to paulen

Fix bug with PWG Stuffs block containing thumbnails

New languages:
* Slovak (Slovensky [SK]), thanks to dodo, xpace

technical changes
if you have any problem with the configuration, go to the config page, check your params and submit the form (anyway)

13 new languages

compatible with Piwigo 2.5

-multisize button is disabled for photos with a backside
-with Piwigo 2.4, backside won't appears at first load if not in the cache (just refresh the page)

fix errors during activation and while the plugin tries to update verso information

solve prefilter issue which masks recto-verso properties on picture modify page

nouveau paramètre : marquer les images ayant un verso sur la page miniatures
meilleure intégration du bouton dans la barre d'outils
utilise le nouveau selecteur pour l'image : moins de bugs

add Italiano, thanks to rio

Nouvelles options :
- position du lien (haut, bas, barre d'outils)
- personnalisation du texte du lien

First public version