* dygraph translation

* cn doc bug fix

* translate dygraph according to 1.5.1 website + bug fix

* update 1.5.1 cn API

* add url

* add windows install whl

* whl and bug

* fix some bugs

* add retinanet_target_assign + focal_loss (#969)

* break up layers and change index of layers (#970)

* break up layers and change index of layers

* prettify script

* update api_cn; fix the error of reverting layers_cn to 1.4; include previous changes

* update layers_cn; add code example to elementwise_mod

* delete recordio_writer_cn; revert index_cn

* update api_cn after review

* fix io_cn.rst

* update layers_cn

* update io_cn

* TRT预测库仅支持GPU编译

DLTP-739 完善tensorRT使用文档 TRT需要GPU编译

* DLTP-965 预测模型的保存和加载文档优化

* Windows_installation_English

* DLTP-1417 受训改为训练

* modify write_docs_cn, write_docs_en, include specifications about python 2.7.15 and creating  virtual env with conda

* gitignore update

* revert .gitignore;  update write_docs

* icafe DLTP-1328, stress  exe.close()

* DLTP-1383 不可迭代更正

* DLTP-1404 修复动态图文档中每段代码的格式和大小都不一样

* DLTP-1390 Pyreader中文显示格式问题

* DLTP-1393 无效链接

* DLTP-1421 paddle.fluid.layers.reduce_max中文翻译有问题

* DyGraph 调整标签结构

* add flag files

* add flags file

* delete space

* recheck_structure&fix_typo

* fix_structure

* adjust_dist_structure

* fix_deadlink

* fix deadlink

* api modification

half modification of fluid/io/layers

* Apply suggestions from code review
Co-Authored-By: Nzy0531 <48094155+zy0531@users.noreply.github.com>

* Update fluid_cn.rst

* fix wrong apis in #767

* Textual proofreading

* 1.3 => develop (4.12)

* Delete InMemoryDataSet and QueueDataSet 

refer to #784

* add pixel shuffle and in_dygraph_mode

* api_trans_0410

* Update io_cn.rst

* Apply suggestions from code review

* fix bugs

* Fix arguments according to 1.3 en + ceil,floor trans +operator trans

* fix LoDTensorArray spell

* 1220 update cnapi

* Apply suggestions from code review
Co-Authored-By: Nhaowang101779990 <31058429+haowang101779990@users.noreply.github.com>

* routine bug fix

* update text info

* fix io_cn all

* 持久性变量=>长期变量

* fix textual content

* fix issue #682 3 3.2

* fix issues in conv

Signed-off-by: Nzhaoyuchen <zhaoyuchen01@baidu.com>

* Update cn api to 1.3 fluid & layers

* Rest to 1.3

* debug

* fix 2 -conv2d

* "锚" ==> anchor(s)

add explanation of auc