def invisible_captcha(honeypot = nil, scope = nil, options = {})
      if InvisibleCaptcha.timestamp_enabled
        session[:invisible_captcha_timestamp] = Time.zone.now.iso8601
      end
      build_invisible_captcha(honeypot, scope, options)
    end
def invisible_captcha(honeypot = nil, scope = nil, options = {})
      if InvisibleCaptcha.timestamp_enabled
        session[:invisible_captcha_timestamp] = Time.zone.now.iso8601
      end
      build_invisible_captcha(honeypot, scope, options)
    end
Builds the honeypot html

 @param honeypot [Symbol] name of honeypot, ie: subtitle => input name: subtitle
 @param scope [Symbol] name of honeypot scope, ie: topic => input name: topic[subtitle]
 @param options [Hash] html_options for input and invisible_captcha options

 @return [String] the generated html