Checked compatibility with Piwigo 2.5

- Added and update languages

* Dutch (Nederlands NL) Thanks to Mattias
* Spanish (Español ES) Thanks to jpr928
* Latvian (Latviešu LV) Thanks to Aivars Baldone
* Russian (Русский - RU) Thanks to kiddy-admin
* Chinese (简体中文 CN) Thanks to winson
* Slovak (Slovensky SK) Thanks to dodo
* Czech (Česky CZ) Thanks to webprostor
* German (Deutsch DE) Thanks to el ninjo
* Polish (Polski PL) Thanks to Greybrow
* Ukrainian (Українська UA) Thanks to animan
* Portuguese (Português PT) Thanks to ANO
* Catalan (Català CA) Thanks to AlbertParera and
* Greek (ελληνικά GR) Thanks to Vasilis Fotopoulos
* Serbia (Srpski – sh_RS) Thanks to vladamilanovic
* Swedish (Svenska - sv_SE) Thanks to styxsailor
* Dansk (Danish - da_DK) Thanks to Egorip and Kaare
* Bulgarian (Български - BG) Thanks to turnokopa
* Thaï (ภาษาไทย TH) Thanks to Pradit Saenkaew
* Brasil (Brazil - pt_BR) Thanks to oigreslima