Enable nested WhileOp

Add dropout sigmoid op converter for trt

[WIP] Feature/eager delete tensor

Doc

Fix sentiment dataset

Accelerate python35 ci job

Fix #12578: Wrong error message when run out of GPU memory

Delete unnecessary explanations

modified error_info for maxout_op

Refine/op/lstm

add unitttest for mac on ci after some untest being disable

* Implement slice grad operator. #8130
* test slice grad operator and bug fix
* Fix pre commit style

Add error info & remove data sharing between input and output in rnn_…

* Create a new paddle build option to build documentation library

* only build copy_paddle_pybind

* Update the to build paddle_python

* build everything

* Use DWITH_FLUID_ONLY

* add build lite

* add a smaller lib

* Update the gen_doc_lib function to handle multiple cases.

* Prevent Paddle triggering documents deployment.

simple fix

Use memcpy to rewrite the sequence pooling LAST and FIRST mode

add error_info for prelu_op

* hotfix for PaddleTensor buffer.

fix text_classification download error

fix redundant args of lambda and remove exception of destructor

add analysis vis ut