Created by: lcy-seso

As discussed, it is necessary to add more example configurations for PaddlePaddle, so that users can better know about how to use PaddlePaddle layers through examples. There may be two ways to do this, I hope to collection ideas about which one is better.

1. Do not remove the current demos directory, and add new example to it.
2. Create a new repo (like Tensorflow https://github.com/tensorflow/models).

Either way, each example has its own directory, we can put configuration file and doc in it.