JD Installer: Detect user OS' language and set as default
|Target version:||040 - FarfarAway|
When installing, JD should detect the user OS' language and set it as default.
If the language is not supported yet, English should be the default language.
In this case the user might be asked to become a translator.
Notes: The question in the current installer, which language should be set as default, is stated in English. Instead of the way mentioned above, JD might display all of JD's supported languages, when installing. This would be more comfortable for the user.