Fin offending utf chars

fi_utf.rb

Dir.glob(File.join('**', '*.coffee')).each do |path|
  File.open(path, 'r+') do |file|
    string = file.read
    string.encode!('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
    file.rewind
    file.write(string)
  end
end