[lang] update of internal addon language files
[lang] update of core language files
[lang] update of skin.confluence language files
[lang] added langinfo.xml for new language Latvian
[lang] added langinfo.xml for new language Faroese
[lang] added langinfo.xml for new language Welsh
Merge pull request #2662 from alanwww1/transifex-frodo-update

[lang] Update of language files from Transifex