Rolling Pictures Captcha Plugin

As an admin, I want to have a plugin for captcha with rolling images so that the capture is hard to guess by bots and is easier to understand by humans

Acceptance Criteria:

• Rolling Pictures plugin for captcha with similar algorithm should be implemented:
  http://notcaptcha.webjema.com/wp-login.php?action=register
• If plugin is enabled, a captcha with images to roll is shown in Sign Up dialog and on SIgn Up page (http://uat.jtalks.org/jcommune/user/new) between Repeat password field and Sign Up button
• Given I'm on Configuration Page of the plugin:
  • I can see all available pictures as a grid, I can upload new ones, remove existing images.
  • I can configure the amount of images will be shown during registration
  • I can configure the amount of sides they can turn over
• I8n should be done in scope of this task.