Add new translations (Polish,Indonesian,Kannada)
    
    Add 3 new translations for Polish, Indonesian, Kannada.
    
    Remove the dummy Italian translation (it.po), it's only purpose was to
    have some translation in the tarball so %{find_lang} wouldn't fail.
    
    Add a new file contributing_translators.txt so we can track our
    translators contributions and give them credit.