[LangInfo] Use preferred audio/subtitle language also for dvds and blurays.
[LangInfo] Use gui's language for dvd/bluray menus.
[LangInfo/AddonManager] Use gui's language for translation in CAddonMgr::GetTranslatedString.
Merge pull request #3375 from ace20022/langinfo

[Langinfo] Use preferred audio/subtitle language for dvds and blurays.