Recognize digits new api first draft

fix deadlinks in index.html and index.cn.html

fix deadline in machine_translation/README.cn.md

update docs

fix math formula bug

fix quick start for fluid, add model tar #9660

update IP to new node

Fix typo of RNN formula

Rewrite formula in MathJax so that it can be rendered correctly.

Fix typo in conv_layer.png

fix "No newline at end of file"

repair dead links

repair 最后一行空行 in index.cn.html

	修改：     README.md

change "新手入门" to "线性回归"