Added single helper to preview arguments.

With that kind of helper it's easy to override it in any rails application to maintain potential security issue on production environments where many of arguments might be considered harmful when seen.

Example in Rails:
```ruby
FILE: config/initializers/resque_web.rb

module Resque
  class Server
    helpers do
      def show_job_arguments(args)
        Array(args).map do |a|
          if a.is_a?(Hash)
            ActionDispatch::Http::ParameterFilter.new(Rails.application.config.filter_parameters).filter(a)
          else
            a
          end
        end.inspect
      end
    end
  end
end
```

This way someone can filter confidential data just from his application.rb configuration for the same params that are filtered across the app and logs.