message: Added gif with survey example into github README
diff: **survey.js** is a JavaScript Survey Library. It is a modern way to add a survey to your website. It uses JSON for survey metadata and results.
  [![Build Status](https://travis-ci.org/andrewtelnov/surveyjs.svg?branch=master)](https://travis-ci.org/andrewtelnov/surveyjs)
  +
  +![alt tag](https://raw.githubusercontent.com/andrewtelnov/surveyjs/master/survey_product_feedback.gif)
  +
  ##Getting started
  [![Join the chat at https://gitter.im/andrewtelnov/surveyjs](https://badges.gitter.im/andrewtelnov/surveyjs.svg)](https://gitter.im/andrewtelnov/surveyjs?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
  