LangInfo::Load: refactoring: allow to check-load language
LangInfo: add static function 'CheckLanguage' and non-static function 'CheckLoadLanguage'
LangCodeExpander: update 'ConvertTwoToThreeCharCode' and 'ConvertToThreeCharCode'
* Fix: Don't update global locale, when checking for language
* Unify Win32 and POSIX versions
* Ability to skip check of XBMC-specific locales
LangInfo::Load: fix: prevent possible endless recursive loop
LangCodeExpander::ConvertToTwoCharCode: fixes: don't update global locale, prevent possible endless recursive loop