message: move README's key feature
diff: We consider deploying deep learning inference service online to be a user-facing application in the future. **The goal of this project**: When you have trained a deep neural net with [Paddle](https://github.com/PaddlePaddle/Paddle), you are also capable to deploy the model online easily. A demo of Paddle Serving is as follows:
  +<h3 align="center">Some Key Features of Paddle Serving</h3>
  +
  +- Integrate with Paddle training pipeline seamlessly, most paddle models can be deployed **with one line command**.
  +- **Industrial serving features** supported, such as models management, online loading, online A/B testing etc.
  +- **Highly concurrent and efficient communication** between clients and servers supported.
  +- **Multiple programming languages** supported on client side, such as C++, python and Java.
  +
  - Any model trained by [PaddlePaddle](https://github.com/paddlepaddle/paddle) can be directly used or [Model Conversion Interface](./doc/SAVE_CN.md) for online deployment of Paddle Serving.
  - Support [Multi-model Pipeline Deployment](./doc/PIPELINE_SERVING.md), and provide the requirements of the REST interface and RPC interface itself, [Pipeline example](./python/examples/pipeline).
  - Support the model zoos from the Paddle ecosystem, such as [PaddleDetection](./python/examples/detection), [PaddleOCR](./python/examples/ocr), [PaddleRec](https://github.com/PaddlePaddle/PaddleRec/tree/master/tools/recserving/movie_recommender).
  @@ -197,14 +204,6 @@ the response is
  {"result":{"price":[[18.901151657104492]]}}
  ```
  -<h2 align="center">Some Key Features of Paddle Serving</h2>
  -
  -- Integrate with Paddle training pipeline seamlessly, most paddle models can be deployed **with one line command**.
  -- **Industrial serving features** supported, such as models management, online loading, online A/B testing etc.
  -- **Distributed Key-Value indexing** supported which is especially useful for large scale sparse features as model inputs.
  -- **Highly concurrent and efficient communication** between clients and servers supported.
  -- **Multiple programming languages** supported on client side, such as Golang, C++ and python.
  -
  <h2 align="center">Document</h2>
  ### New to Paddle Serving
  