This reverts commit cb92d4e2.

* latest install doc

* latest install doc

* Rename install_doc.rst to install_doc.md

* add install_doc.md to path

* Fix flowers dataset download problem

* Simply modify beginners_guide/basics/image_classification/index.md
to have the $math$ format instead of `$math$`

* Update the rest of the documentation to move away from `$$` format

* Add pics of Anakin tutorial

* Update anakin_tutorial.md

* Delete anakin_fm_en.png

* Delete contri1.JPG

* Delete contri2.JPG

* update windows install doc

* Update install_doc.rst

* Update install_doc.rst

* Update install_doc.rst

* Update install_doc.rst

* Create faq.rst

* Update index_cn.rst

* Update index_cn.rst

* delete video

* delete video link of recognize_digits

* delete video link of image_classification

* delete video link of label_semantic_roles

* delete vedio link of machine_translation

* delete video link of recommender_system

* delete video link of understand_sentiment

* delete video link of word2vec