Fixes wrong links to documents in Chinese

This English document should link to the English version of other documents.

Refine DSSM.

Update README.md

增加数据来源信息。

说明数据集来源

Implement Inception-v4 for image classification

fix typo

we use `infer.py` to predict.

Add the Inception-ResNet-v2 model.

Refine the readme.md of DSSM.

use clang_format having the same version with the Paddle main repo.

remove the useless directory for c-api.

Update the CTR image and description.

Fix README of nce_cost.

fix ci.

The new image is a courtesy of Varun

Fix the output of cnn in DSSM.

fix urls in nmt_without_attention's doc

Fix resnet_cifar10 in image_classification.